Timeline of Iran's Nuclear Activities

October 11, 2010
Semira N. Nikou
 
1957
The United States and Iran signed a civil nuclear cooperation agreement as part of the United States Atoms for Peace program. The agreement provided for U.S. technical assistance and the lease of enriched uranium to Iran. It also called for research cooperation on peaceful nuclear energy uses.
 
1967
November – The Tehran Nuclear Research Center, supplied by the United States, opened. It was equipped with a 5-megawatt nuclear research reactor called the Tehran Research Reactor (TRR), fueled by highly enriched uranium.
 
1968
July 1 – Iran signed the Nuclear Non-Proliferation Treaty (NPT). Parliament ratified it in February 1970. Uranium enrichment was allowed under the treaty.
 
1974
May 15 – Iran signed the NPT’s Safeguards Agreement with the International Atomic Energy Agency (IAEA). The safeguards allowed inspections for the purpose of verifying that nuclear enrichment for peaceful nuclear energy is not diverted to nuclear weapons or other nuclear explosive devices.
 
November – West German company Kraftwerk Union, a subsidiary of Siemens, agreed to construct two 1,200-megawatt light water reactors to produce nuclear energy at Bushehr. Construction began in August 1975, but the formal contract was not signed until mid-1976.
 
1975
The Ford administration expressed support in principle for the shah’s plan to develop a full-fledged nuclear power program to diversify Iran’s energy sources. The shah wanted the capacity to generate 23,000 megawatts of electricity with the ability to reprocess U.S.-supplied fuel.
 
1976
April 20 – President Gerald Ford issued National Security Decision Memorandum 324 supporting the shah’s ambitions and helping Iran formulate a plan to build 23 nuclear power reactors. But the administration refused to allow Iran to have the independent reprocessing capabilities sought by the shah. Ford’s memorandum instead approved a multinational reprocessing plant in Iran that would also enable the United States to participate in the project. Iran rejected the multinational option and pushed for a comprehensive national nuclear program.
 
1977
August - President Carter reopened negotiations on the shah’s quest for a nuclear energy program.
 
1978
January – Iran and the United States initialed a nuclear agreement in which Iran agreed to safeguards beyond NPT requirements. In return, the United States granted Iran "most favored nation" status for reprocessing so that Iran would not be discriminated against when seeking permission to reprocess U.S.-supplied fuel.
 
1979
After the 1979 revolution, the United States stopped supplying highly enriched uranium for the Tehran Research Reactor.
 
July 31 – Kraftwerk Union terminated work on the Bushehr reactor when Iran failed to make payments.
 
1984
February – German engineers returned to Iran to do a feasibility study to complete the Bushehr reactor.
 
March 24 – Iraq’s attack on the Bushehr nuclear power plant did serious damage.
 
December – Iran opened a nuclear research center at Isfahan with China’s assistance. In 1985, China supplied the center with a "training reactor."
 
1987
May 5 – After 18 months of negotiations, Argentina concluded a $5.5 million deal with Tehran to supply a new core for the Tehran Research Reactor so it would operate with only 20 percent enriched uranium, instead of the previous 90 percent. In 1989, Argentina replaced the core. In 1993, Argentina delivered around 50 pounds of 20 percent enriched uranium to fuel the reactor.
 
1990
Oct. 9 – Iran decided to rebuild the damaged Bushehr nuclear power plant.
 
1992
Aug. 25 – Russia and Iran signed a cooperation agreement on the civil use of nuclear energy, including construction of a nuclear power plant.
 
1995
January –Iran signed a contract with the Russian Ministry of Atomic Energy to build a light water reactor at Bushehr under IAEA safeguards. Russia was under a contractual obligation to complete the plant within 55 months. The project’s completion was delayed until August 2010.
 
1997
May – The IAEA expanded the Safeguards Agreement by adopting the Additional Protocol. Under the latter, inspectors would be allowed to conduct short notice inspections and be provided with multiple entry/exit visas. Iran signed the Additional Protocol in 2003, but had not ratified it as of 2010.
 
1998
Feb. 23 – The Clinton administration opposed Iran's nuclear energy program on grounds that Iran had sufficient oil and gas reserves for power and that work on the nuclear power reactor could indirectly contribute to a weapons program.
 
March 6 – Under U.S. pressure, Ukraine announced that it would not sell two turbines for use at the Bushehr reactor.
 
 
1999
May 7 Russia said Iran wanted to expand nuclear cooperation, potentially including the building of a second nuclear power plant.
 
May 19 – President Mohammad Khatami paid a five-day state visit to Saudi Arabia, where Iran and Saudi Arabia issued a joint statement expressing support for turning the Middle East into a zone free of weapons of mass destruction. They said Israel's production and stockpiling of nuclear weapons, along with its non-compliance with international laws and treaties, posed a serious threat to peace and security in the region.
 
2000
March 14 – President Clinton signed the Iran Nonproliferation Act, which allowed the United States to sanction individuals and organizations providing material aid to Iran’s nuclear, chemical, biological and ballistic missile weapons programs.
 
2001
March 12-15 – Russian President Vladimir Putin and Iranian President Khatami signed nuclear and military cooperation accords. Khatami said Iran wanted a second nuclear power plant after the completion of Bushehr.
 
2002
Jan. 8 – Former President Akbar Hashemi Rafsanjani said, "Iran is not seeking to arm itself with non-conventional weapons."
 
Aug. 15 – The National Council of Resistance of Iran, an exiled opposition group, revealed that Iran was building two secret nuclear sites – a uranium enrichment plant and research lab at Natanz and a heavy water production plant in Arak. President Khatami acknowledged the existence of Natanz and other facilities on Iran's state-run television and invited the International Atomic Energy Agency to visit them.
 
Sept. 1 – Russian technicians began to assemble heavy equipment in the Bushehr reactor, despite U.S. attempts to convince the Russians not to participate. But the plant faced frequent delays in construction.
 
2003
Feb. 9President Khatami said Iran had discovered and extracted uranium in the Savand area. He cited Iran’s “legitimate right to obtain nuclear energy for peaceful aims” and expressed readiness to accept international inspections of its nuclear activities. 
 
May 6 – Iran’s Atomic Energy Organization presented the United Nations with a sketch of Iran's nuclear program, insisting that the program was peaceful.
 
May 17 – Tehran backed a proposal by Syria to rid the Middle East of weapons of mass destruction.
 
June 19 – An IAEA report did not find Iran in violation of the NPT but said Iran should have been more forthcoming about the Natanz uranium enrichment facility and the Arak heavy water production plant. The U.N. watchdog agency later urged Iran to sign and ratify the Additional Protocol to the Safeguards Agreement of the Nuclear Non-Proliferation Treaty, which would allow inspectors more access to nuclear sites and the right to sudden inspections.
 
Aug. 26 – IAEA inspectors found traces of highly enriched uranium at Iran's Natanz nuclear plant. Iran claimed the traces came from equipment imported from another country.
 
Sept. 19 – President Khatami said, "We don't need atomic bombs, and based on our religious teaching, we will not pursue them...but at the same time, we want to be strong, and being strong means having knowledge and technology."
 
Sept. 25 – U.N. weapons inspectors found traces of highly enriched weapons-grade uranium at a second site near the capital city of Tehran. The IAEA set a deadline of Oct. 31 for Iran to prove it was not making nuclear weapons. 
 
Oct. 21 – In talks with Britain, France and Germany (EU-3), Iran agreed to suspend uranium enrichment and processing activities and to open nuclear sites to unannounced inspections by the U.N. watchdog agency. It also agreed to sign the Additional Protocols of the Non-Proliferation Treaty and its safeguards agreement with the IAEA. 
 
Oct. 24 – 1,500 Iranian protestors gathered in Tehran to denounce the recently concluded agreement between Tehran and the EU-3.
 
Nov. 12 – The IAEA concluded there was no evidence of a secret nuclear weapons program in Iran but showed concern about its production of plutonium. President Khatami said that the plutonium was used for manufacturing pharmaceuticals and the small amount produced by Iran could not make a nuclear bomb. 

Dec. 18 – Tehran signed the Additional Protocol to the Non-Proliferation Treaty’s Safeguards Agreement. The Additional Protocol granted IAEA inspectors greater authority in their nuclear verification programs. Since then, Iran has at times voluntarily allowed more intrusive inspections, but the Iranian parliament has not yet ratified the Additional Protocol.
 
2004
Feb. 22 Iran acknowledged having secretly bought nuclear parts from international sources, although Tehran continued to insist that its goal was electricity production and not nuclear weapons.
 
Apr. 7 – Iran declared its plans to construct a heavy water reactor to produce radioisotopes for medical research. Western envoys warned that the facility could reprocess the spent fuel rods to produce plutonium.
 
Aug. 28 – President Khatami said Iran had a right to enrich uranium and was willing to provide guarantees to the IAEA that it was not developing nuclear weapons.
 
Oct. 6 – Tehran announced that it had produced tons of the hexafluoride gas needed to enrich uranium by converting a few tons of yellowcake uranium.
 
Nov. 14 – In negotiations with Britain, France and Germany, Iran accepted the Paris accord, which recognized Tehran's rights to pursue nuclear technology for peaceful purposes and reaffirmed Iran's commitment not to acquire nuclear weapons. In exchange, Iran voluntarily agreed to temporarily suspend uranium enrichment activities and allow the IAEA to monitor the suspension.
 
Nov. 15 – The IAEA reported that it had not found any evidence that Iran had tried to develop nuclear weapons, although it could not rule out the existence of nuclear materials that had not been declared.
 
Nov. 22 – Iran invited the IAEA to monitor the suspension of all enrichment-related activities.
 
Nov. 30 – Iran said that it had not abandoned its right to enrich uranium and that the suspension was only temporary. European officials hoped to make the suspension permanent in return for trade deals and other incentives.
 
Dec. 22 – Iran’s intelligence minister announced the arrest of more than 10 people on spying charges. Tehran charged the spies were passing sensitive information on Iran’s nuclear program to the Israeli Mossad and the CIA.
 
2005
Jan. 13 – IAEA inspectors were only allowed partial access to the Parchin military base near Tehran. Under the NPT, Iran was not required to allow inspectors into its military bases. But the Bush administration consistently expressed concern that Iran’s failure to allow full access to its suspected military bases and facilities was linked to a secret nuclear weapons program.
 
Jan. 17 – President Bush said military action against Iran remained an option, "if it continues to stonewall the international community about the existence of its nuclear weapons program." 
 
Feb. 7 - Iran's Minister of Defense Ali Shamkhani said in an interview that it was not in Iran's national interest to acquire nuclear weapons.
 
Feb. 28 – Tehran and Moscow signed an agreement that stipulated that Russia would supply nuclear fuel for the Bushehr facility and that Iran would return all spent fuel rods to Russia to ensure the fuel was not diverted for other use.
 
May 15Iran’s parliament approved a non-binding resolution urging the government to resume uranium enrichment for peaceful use.
 
Aug. 1 – Iran informed the IAEA that it had decided to resume activities at the Isfahan uranium conversion center. The U.N. nuclear watchdog agency urged Iran not to take any action that would prejudice negotiations with Britain, France and Germany (the EU-3) or undermine the IAEA inspection process.
 
Aug. 5 – Britain, France and Germany (the EU-3) proposed the “Framework for a Long-term Agreement” to Iran. The deal offered assistance in developing peaceful nuclear energy in exchange for a binding commitment that Iran would not to pursue fuel cycle activities other than for light water power and research reactors. It also called for a halt on construction of a heavy water research reactor at Arak. Iran rejected the proposal, as it required Tehran to abandon all nuclear fuel work.
 
Aug. 8 – Iran resumed uranium conversion at the Isfahan facility under surveillance of the IAEA.
 
Aug. 9 – Supreme Leader Ayatollah Ali Khamenei issued a fatwa forbidding the “production, stockpiling and use of nuclear weapons.”

Aug. 11 –The IAEA urged Iran to suspend all enrichment activities and re-instate IAEA seals.
 
Sept. 24The IAEA found Iran in noncompliance with the NPT Safeguards Agreement and decided to refer Tehran to the U.N. Security Council for further action. The decision followed Iran’s repeated failure to fully report its nuclear activities. Tehran countered that it might suspend its voluntary implementation of the Additional Protocol that allowed more intrusive and sudden inspections.
 
Nov. 20 –Iran’s parliament approved a bill requiring the government to stop voluntary implementation of the Safeguards Agreement’s separate Additional Protocol, which allowed more intrusive and surprise inspections, if Iran were referred to the Security Council. The parliament did not move to block normal inspections required under the Safeguards Agreement, which had been ratified by parliament in 1974.
 
2006
January Iran broke open internationally monitored seals on the Natanz enrichment facility and at two related storage and testing locations, which cleared the way to resume nuclear fuel research under IAEA supervision. 
 
Feb. 4 The IAEA voted to report Iran to the U.N. Security Council for its non-compliance with its NPT Safeguards Agreement obligations.
 
July 31 The U.N. Security Council passed Resolution 1696 demanding that Iran suspend its uranium enrichment activities within one month. No sanctions were imposed but the resolution warned that "appropriate measures" would be taken in the case of Iranian non-compliance. Tehran called the resolution illegal.
 
Aug. 26 – Iran's President Mahmoud Ahmadinejad inaugurated a heavy water production plant at Arak. The United States expressed concern that the heavy water would be used in the heavy water reactor at Arak to produce plutonium, an ingredient in making nuclear weapons.
 
Oct. 2 – President Bush signed into law the Iran Freedom Support Act, which imposed economic sanctions on nations and companies that aided Iran's nuclear program.
 
Dec. 23 – The U.N. Security Council adopted Resolution 1737, sanctioning Iran for its failure to comply with Resolution 1696 and halt uranium enrichment. The resolution banned the sale of nuclear-related technology to Iran and froze the assets of key individuals and companies related to the nuclear program.
 
2007
March 24 – The U.N. Security Council adopted Resolution 1747, which banned the sale of arms to Iran increased the freeze on assets.
 
Dec. 4 – A U.S.National Intelligence Estimate on Iran's nuclear activities said there was evidence that Tehran halted its nuclear weapons program in 2003. It assessed with “moderate confidence” that Iran had not re-started its nuclear weapons program as of mid-2007. The findings contradicted the 2005 U.S. intelligence assessment that Tehran was seeking nuclear weapons capability.
 
2008
Feb. 22 – An IAEA report concluded that Iran had not fully answered the international community's questions about its nuclear program and testing of new centrifuge technology for faster uranium enrichment. The report was based in part on intelligence acquired by the Bush administration that allegedly pointed to Iranian efforts to weaponize nuclear materials. The data was extracted from a laptop reportedly smuggled out of Iran in 2004.
 
March 3 – The U.N. Security Council approved Resolution 1803, imposing further economic sanctions on Iran.
 
July 18 – The Bush administration agreed to send U.S. Undersecretary of State William Burns to Geneva to participate with his European counterparts in talks with Iran about its nuclear program. But Iran again rejected the suspension or freeze of its enrichment activities. 
 
Sept. 26 The U.N. Security Council passed Resolution 1835 which reaffirmed three earlier rounds of sanctions against Iran. No new sanctions were imposed, largely because of objections by Russia and China.
 
2009
Sept. 25 – President Obama, French President Sarkozy and British Prime Minister Brown told a press conference that Iran had a covert fuel enrichment plant near Qom. Iran said it had already confirmed the construction of a new pilot enrichment plant to the IAEA in a letter four days earlier. Critics said Tehran disclosed the site once it discovered the facility was already under surveillance.
 
Oct. 1 – Iran met in Geneva with permanent members of the U.N. Security Council and Germany to discuss Iran's nuclear program. The parties outlined a proposal for Iran to ship 80 percent of its stockpile of low-enriched uranium from Natanz to Russia. The shipment would then go to France for further enrichment and fabrication of fuel rods for the Tehran Research Reactor, which produced isotopes for medical use.
 
Oct. 19-21The early October talks in Geneva were continued in Vienna with the presence of the IAEA, on the transfer of Iran’s low-enriched uranium. A consensus was reached on a draft agreement. The United States, France and Russia approved the agreement, but Iran backed down due to domestic opposition.
 
2010
Feb. 12 – President Ahmadinejad announced that Iran had produced 20 percent enriched uranium, up from 3.5 percent, in a move that marked a major increase in its capabilities. He said Iran had the capability to enrich the fuel even further.
 
May 17 – Turkey, Brazil and Iran agreed to a nuclear deal similar to the agreement outlined in Geneva in 2009. The proposal called for the transfer of 1,200 kg of low-enriched uranium (3.5 percent) to Turkey, in exchange for 120 kg of 20 percent enriched uranium needed to run the Tehran Research Reactor. The United States and Europeans rejected the deal because Iran had increased its uranium stockpile. The 1,200 kg then represented only about half of Iran’s stockpile, rather than the 80 percent it had in the October 2009 deal. Washington also believed the move was a delaying tactic to avert sanctions.
 
June 9 – The U.N. Security Council adopted Resolution 1929, imposing a fourth round of sanctions on Iran. They included tighter financial measures and an expanded arms embargo. President Ahmadinejad said the sanctions were a "used handkerchief that should be thrown in the dustbin," and that they were "not capable of harming Iranians."
 
June – The Stuxnet computer virus was reportedly detected in staff computers at the Bushehr nuclear plant.
 
June 24 – Congress approved the Comprehensive Iran Sanctions, Accountability, and Divestment Act of 2010. It passed unanimously in the Senate and overwhelmingly in the House. The bill expanded existing U.S. sanctions on Iran. It imposed extensive sanctions on foreign companies that export refined petroleum to Iran or invest in Iran’s energy sector. The legislation went well beyond U.N. Resolution 1929. 
 
July 6 – Iran announced that talks with U.N. Security Council and Germany could begin in September.
 
July 11 – Iran announced it had produced 20 kilograms of 20 percent enriched uranium and had begun work on fuel plates. The fuel was to be delivered to the Tehran Research Reactor by September 2011, for creating medical isotopes. Western powers have repeatedly expressed fear that Iran’s capability to enrich 20 percent would help it produce nuclear weapon material, which is around 90 percent.
 
July 26 – The European Union passed sanctions, which banned technical assistance to Iran’s oil and gas industry.
 
Aug. 13 – The Russian Federal Atomic Energy Agency (Rosatom) announced that the first reactor at the Bushehr would soon be loaded with nuclear fuel and become Iran’s first operational nuclear power plant.
 
Aug. 21 – An official launch ceremony was held to mark completion of the Bushehr reactor, after years of delays. Iran began loading the plant with fuel, in hopes of making it fully operational within a few months. As part of the deal, Russia supplied the reactor with fuel and Iran is required to send back the spent fuel to Russia.
 
Nov. 23 – An IAEA report showed that Iran stopped uranium enrichment for one day on Nov. 16, 2010 with no reasoning provided. This report came amid speculation that Iran’s nuclear program had suffered technical problems.
 
December - Iran began producing its own yellowcake, which is necessary for the production of nuclear reactor fuel. Sale of yellowcake to Iran is banned under U.N. sanctions.
 
Dec.6-7 – Iran met in Geneva with members of the U.N. Security Council and Germany for negotiations over Iran’s nuclear program. The group agreed to meet again in January 2011 in Istanbul.
 
2011
Jan. 8 - Nuclear chief Ali Akbar Salehi claimed that Iran had the necessary technology to make fuel plates and rods for its nuclear reactors.
 
Jan. 21-22 – P5+1 talks in Istanbul failed after Tehran refused to discuss transparent limits on its uranium enrichment program.
 
Feb. 25 – An IAEA report found new information suggesting that Iran may have worked on nuclear weapons research. It also noted that Iran appeared to have overcome setbacks from the Stuxnet virus.
 
May 10 – Iran’s Bushehr nuclear power plant began operating at a low level, according to the Russian company that built it, Atomstroyexport.
 
May 23-24 – The E.U. imposed sanctions on more than 100 individuals and companies tied to Iran's nuclear program while the United States sanctioned seven foreign companies involved in supplying Iran with refined oil. It also blacklisted sixteen firms and individuals involved in the missile and nuclear programs.
 
May 24 – An IAEA report found that Iran had significantly increased its low-enriched uranium production and slightly increased its number of centrifuges.
 
Sept. 2 – An IAEA report found that Iran had not suspended its uranium enrichment related activities and was not cooperating enough with the IAEA.
 
Sept. 4 - Iran announced that Bushehr nuclear power plant had been connected to the national power grid.
 
Nov. 8 - An IAEA report claimed that Iran had continued nuclear weaponization work since 2003 and that Iran had a secret project to enrich uranium. It also indicated that there were 8,000 centrifuges installed at Natanz, 6,200 of which were operating. Tehran claimed that the U.S. had fabricated the evidence.
 
Nov. 18 – The IAEA Board of Governors adopted a new resolution on the implementation of safeguards and relevant provisions of the U.N. Security Council resolutions in Iran. The resolution expressed “deep and increasing concern about the unresolved issues regarding the Iranian nuclear program, including those which need to be clarified to exclude the existence of possible military dimensions.”
 
2012
Jan. 1 – Iran’s nuclear agency reported that Iranian scientists have produced their first nuclear fuel rod.
 
Jan. 9 – The IAEA confirmed that Iran has begun enriching uranium at its underground plant at Fordow to 20 percent.
 
Jan. 23 – The European Union imposed an oil embargo on Iran, effective July 1, 2012. The European Union made up 20 percent of Iran’s oil sales.
 
Feb. 15 – In a live television broadcast, President Ahmadinejad unveiled Iran’s first domestically produced batch of 20-percent enriched nuclear uranium for Tehran's research reactor. Iran also activated a new generation of centrifuges that reportedly increased its enrichment capacity threefold.
 
Feb. 21 – IAEA inspectors left Iran after being denied access to the Parchin military base.
 
Feb. 24 – An IAEA report found that Iran has significantly stepped up its uranium enrichment program. The IAEA expressed “serious concerns” about potential military uses.
 
March 6 – The P5+1 agreed to resume talks with Iran over its nuclear program.
 
April 14 – The P5+1 met in Istanbul to discuss Tehran's promised “new initiatives” on its nuclear program.
 
May 23-24 – The P5+1 held inconclusive talks with Iran in Baghdad.
 
May 25 – An IAEA report stated that inspectors found traces of uranium enriched to 27 percent at Fordow. It concluded that Iran is “unable to provide credible assurance about the absence of undeclared nuclear material and activities in Iran, and therefore to conclude that all nuclear material in Iran is in peaceful activities.”
 
May 28 – Iran acknowledged that the Flame computer virus had infiltrated its computer system.
 
June 18-19 – The P5+1 held inconclusive talks with Iran in Moscow.
 
July 12 – The United States announced broad new sanctions on Iranian front companies and banks linked to the proliferation of nuclear and missiles programs. 
 
Aug. 30 – An IAEA report found that Iran had doubled its production capacity at Fordow. It warned that Iran had “sanitized” a suspect site at the Parchin military complex in ways that “significantly hampered” the agency’s investigation into  past activities.
 
Oct. 15 – The European Union targeted Iran’s nuclear program with new sanctions on its financial, energy, trade, and transport sectors. 
 
Nov. 5 – IAEA chief Yukiya Amano announced that his agency “cannot conclude that all nuclear material in Iran is in peaceful activities.” Talks between Tehran and the IAEA since November 2011 had not delivered “concrete results,” he said in an annual report to U.N. General Assembly.
 
Nov. 16 – An IAEA report found that Iran was continuing to enrich uranium, upgrade its facilities and build a heavy water reactor. Since the last quarterly report, Tehran has added 43 kilograms of 20 percent-enriched uranium to its stockpile.
 
Dec. 13 – The U.S. Treasury and State Department imposed sanctions on seven Iranian companies and five individuals for “proliferating weapons of mass destruction” pursuant to Executive Order 13382.
 
Dec. 21 – The U.S. Treasury Department froze the assets of four Iranian companies and one executive for links to Tehran’s missile and nuclear programs.
 
2013
Jan. 16-17 –The IAEA held talks with Tehran over allegations that tests had been carried out for atomic weapons triggers, but failed to produce an agreement.
 
Feb. 2 – Vice President Joe Biden said that the United States is prepared to hold direct talks with Iran to resolve tensions over its controversial nuclear program.
 
Feb. 13 – IAEA experts met in Tehran but failed to finalize an agreement that would allow inspectors to investigate nuclear and military facilities.
 
Feb. 6 - The U.S. Treasury Department imposed new sanctions on the Central Bank of Iran and other financial institutions to restrict Tehran’s ability to spend oil revenues. It also designated one individual and four entities for involvement in censorship activities.
 
Feb. 7 – Supreme Leader Ayatollah Ali Khamenei rejected the offer by Vice President Biden for direct talks. “Some naïve people like the idea of negotiating with America. However, negotiations will not solve the problem,” he said in a speech to Iranian Air Force commanders.
 
Feb. 11 – The U.S. Treasury Department imposed new nonproliferation sanctions on entities and individuals from Belarus, China, Iran, Sudan, Syria, and Venezuela. Credible information indicated that they had transferred to, or acquired from, Iran, North Korea, or Syria, equipment and technology related to weapons programs.
 
Feb. 26-27 – Diplomats from P5+1 countries met with their Iranian counterparts in Almaty, Kazakhstan and agreed to have two more meetings later that spring.
 
March 14 - The U.S. Treasury Department sanctioned a Greek businessman and 14 companies for helping Iran evade international oil sanctions.
 
April – Iran reported that it had begun mining uranium at two locations and started operations at an ore-processing plant.
 
March 18 – President Obama sent a fifth Nowruz message to Iran saying there could be a “new relationship” with Iran if it meets international obligations on its controversial nuclear program.
 
March 21 – Supreme Leader Ayatollah Ali Khamenei said he is not opposed to direct talks with the United States in a speech marking Nowruz. But he is “not optimistic” about prospects for success if negotiations take place. He also claimed that the United States “doesn’t want the nuclear conflict to end.”
 
April 5-6 – Diplomats from P5+1 countries met with their Iranian counterparts in Almaty, Kazakhstan but the talks end without an accord or plans for another meeting. Tehran introduced a proposal requiring world powers to recognize its right to enrich uranium.
 
May 22 – The IAEA reported that Iran had continued installation of advanced IR-2m centrifuges that could significantly upgrade its enrichment capabilities.
 
June 3 – The United States imposed sanctions for the first time on Iran’s currency, the rial. The executive order’s objective was to render the currency unusable outside of Iran, a senior administration official said during a conference call.
 
June 4 – The United States sanctioned a major network of front companies for hiding assets on behalf of Iranian leaders.
 
June 18 – The Group of Eight industrialized nations called on Iran to move “without delay” to fulfill its long-delayed obligations in answering questions about its controversial nuclear program. It also called on the international community to fully implement a several U.N. sanctions resolutions designed to pressure Tehran into compliance. 
 
July 1 – New U.S. sanctions banning gold sales and trade in gold with Iran went into effect.
 
Aug. 28 – The IAEA reported that Iran had made slow but steady progress on its nuclear program since May. Iran continued to install centrifuges but only added a small amount of 20-percent low enriched uranium to its stockpile, which was not sufficient for one bomb’s worth of fuel.
 
Oct. 28-29 – The IAEA held talks with Iran on outstanding issues regarding its nuclear program. Iran “presented a proposal on practical measures as a constructive contribution” to ongoing talks,” according to a joint statement. The sides agreed to meet again November.
 
Sept. 26 – Foreign ministers from P5+1 countries and Iran met on the sidelines of the U.N. General Assembly and agreed to hold a new round of talks in Geneva.
 
Sept. 27 – President Barack Obama called Iranian President Hassan Rouhani in what was the first direct communication between a U.S. and Iranian presidents since the 1979 revolution. “The two of us discussed our ongoing efforts to reach an agreement over Iran’s nuclear program,” Obama said at a White House briefing.
 
Oct. 15-16 – Diplomats from P5+1 countries and Iran met in Geneva to solve the nuclear dispute. They committed to meeting in November to continue talks that were “substantive and forward looking.”
 
Nov. 7-10 – Iran and the P5+1 made significant headway but ultimately failed to finalize an agreement. Foreign ministers rushed to Geneva as a breakthrough appeared imminent. But last-minute differences, reportedly spurred by French demands for tougher terms, blocked a deal.
 
Nov. 11 – IAEA Director General Yukiya Amano visited Tehran. He and Iran’s chief of the Atomic Energy Organization, Ali Akbar Salehi, signed a Framework for Cooperation Agreement committing Tehran to take practical steps towards transparency within three months.
 
Nov. 24 – Iran and the P5+1 reached an interim agreement that would significantly constrain Tehran’s nuclear program for six months in exchange for modest sanctions relief. Iran pledged to neutralize its stockpile of near-20 percent enriched uranium, halt enrichment above five percent and stop installing centrifuges. Tehran also committed to halt construction of the Arak heavy water reactor.
 
Dec. 9 -12 –The P5+1 and Iran met in Geneva at the technical level to discuss implementation of the interim nuclear deal.
 
Dec. 11 – Iran and the IAEA met in Vienna to review the status of the six actions Iran committed to in November as part of the Framework for Cooperation Agreement.  
 
Dec. 19 – Nuclear and sanctions experts from Iran and the P5+1 met in Vienna to discuss technical details related to implementing the interim nuclear agreement. The Iranian team unexpectedly flew back to Tehran, reportedly in response to Washington’s blacklisting of 19 entities for violating sanctions.
 
Dec. 30-31 – The P5+1 and Iran met again in Geneva for technical talks on implementing the November Joint Plan of Action.
 
2014
Jan. 9-12 – The P5+1 and Iran met in Geneva and reach an agreement on implementation. The delegations returned to their capitals for approval. On January 12, the parties announced that the Joint Plan of Action will be implemented starting on January 20.
 
Jan. 20 – The Joint Plan of Action entered into force. The IAEA also issued a report stating that Iran is complying with the deal after reducing their 20% enrichment stockpile and halting work on the Arak heavy water reactor. The United States and European Union announced they have taken steps to waive certain sanctions and release a schedule for releasing Iran’s oil money frozen in other countries.
 
Feb. 6 – The U.S. Treasury announced new measures against more than a dozen companies and individuals deemed to be “evading U.S. sanctions against Iran, aiding Iranian nuclear and missile proliferation, and supporting terrorism.”
 
Feb. 7 – The U.S. Treasury issued a general license allowing Iranians to purchase computers, cell phones, software, mobile applications and Internet services. “We are committed to promoting the free exchange of information in Iran and to enabling individuals in Iran to communicate with each other and with the outside world,” said a Treasury spokeswoman in an email, according to The Wall Street Journal.
 
Feb.18-20 – The P5+1 and Iran agreed on a framework for final negotiations on February 20 after three days of discussion in Geneva.  
 
March 3 – IAEA chief Yukiya Amano announced that Iran has implemented the six measures contained in the Framework for Cooperation Agreement but also notes that “much remains to be done to resolve all outstanding issues.”
 
March 19 – The P5+1 and Iran held another round of closed-door talks on a final nuclear agreement. Ashton and Zarif described their discussions on the Arak heavy water reactor and Western sanctions as “substantive and useful.”
 
March 20 – The IAEA released a report detailing Iran’s implementation of the interim nuclear deal brokered in November 2013. The report noted that Tehran has not enriched any more uranium to 20 percent. But it had not yet completed a facility to convert low-enriched uranium gas into an oxide, which would need to be reprocessed to fuel a weapon.
 
April 7-9 – The P5+1 and Iran met in Vienna to continue negotiations on a final nuclear agreement. Iranian Foreign Minister Mohammad Javad Zarif and E.U. foreign policy chief Catherine Ashton reported that they had “substantive and detailed discussions” on all relevant issues.
 
April 17 – The U.S. State Department announced that Washington had taken steps to release $450 million installment of frozen Iranian funds after the IAEA verified Iran is complying with the interim nuclear agreement.
 
May 13-16 –The P5+1 and Iran met in Vienna to begin drafting a final agreement. The talks ended without any tangible progress. But both sides committed to another round of talks in June.
 
May 21 – Iran and the IAEA agreed to an additional five actions for Tehran to take before August 25. Two of the actions involved Iran providing information on possible military dimensions of its nuclear program.
 
June 9-10 – U.S. Deputy Secretary of State William Burns lead a team of officials to Geneva for bilateral talks with Iran to prepare for the next round of P5+1 talks.
 
June 16-20 – The P5+1 met in Geneva and produced an outline of a draft agreement but did not make much progress on the core issue of uranium enrichment. They agreed to meet on July 2 and hold continuous talks until the July 20 expiration date.
 
July 3-19 – The P5+1 began marathon talks on July 3, less than three weeks form the due date for a deal. After about a week and half of discussions, some foreign ministers, including Kerry, Zarif and Hague, went to Vienna to check on progress of the talks. On June 19, the two sides announced that the will extend the talks through November 24, exactly one year since the interim agreement was brokered. Iran agreed to take further steps to decrease its 20 percent enriched uranium stockpile. In return, the P5+1 nations agreed to repatriate $2.8 billion in frozen funds back to Iran.
 
Sept. 18-26 – Iran and the P5+1 resumed talks on the sidelines of the U.N. General Assembly in New York. Several meetings were held, including a one-on-one meeting between Kerry and Zarif, in which they also discussed the threat posed by the Islamic State in Iraq and Syria. The sides did not reach an understanding on major issues such as uranium enrichment and sanctions relief.
 
Oct. 14-16 – The P5+1 and Iran met in Vienna and made a little progress. Disagreements remained over Tehran’s uranium enrichment capabilities and a timeline for implementing a deal. Officials emphasized that the sides had not given up on the November 24 due-date for a deal and that the talks had focused on a “full agreement,” not just understandings of key issues.
 
Nov. 9-11 – Kerry, Zarif, and Ashton met for two days of trilateral talks in Oman, followed by a day of meetings between Iran and the full P5+1. The removal of sanctions and levels of uranium enrichment were among the issues on the table, but officials did not report any significant progress from this round of discussions.
 
Nov. 19-21 – The final round of talks began in Vienna. On November 19, Zarif and Ashton held a meeting, and the U.S. and Iranian teams held bilateral talks. Kerry arrived in Vienna on November 20 after meeting with Omani Foreign  Minister Yusuf bin Alawi in London and French Foreign Minister Laurent Fabius in Paris. Kerry, Ashton, and Zarif held another round of discussions on November 21, but Zarif noted that he had received "no remarkable proposals to take to Tehran" after the meeting.
 
Nov. 24 – Officials from Iran and P5+1 missed the deadline for a deal and announced that talks will be extended by seven months, with a political agreement to be in place by March.
 
Dec. 17 – Iran and the P5+1 held talks at the deputy level in Geneva. Deputy Foreign Minister Abbas Araghchi told reporters that the “intense negotiations” were “very useful and helpful.” No E.U. statement was released after the talks and the U.S. delegation did not provide comments to the press.
 
2015 
Jan. 14, 16 – Kerry and Zarif met in Geneva to find ways to speed up negotiations. They meet again in Paris later in the week.
 
Jan. 15-17 – Iran and the U.S. hold bilateral talks in Geneva.
 
Jan. 18 – Iran and the P5+1 powers made limited progress in talks in Geneva. They agreed to meet again in early February.
 
Feb. 23 – Iran and the P5+1 concluded another round of talks on Iran's controversial nuclear program in Geneva. Atomic Energy Organization chief Ali Akbar Salehi and U.S. Energy Secretary Ernest Moniz joined the talks for the first time to provide technical expertise, but Secretary of State John Kerry noted that their presence was "no indication whatsoever that something is about to be decided."
 
March 2-5 – Deputy foreign ministers from Iran and the P5+1 resumed talks in Montreux, Switzerland. Separately, Zarif held bilateral talks with Kerry and Russian Foreign Minister Sergei Lavrov in Geneva, joining the rest of the negotiators in Montreux on March 5. 
 
March 16-18 – Kerry and Zarif met in Lausanne, Switzerland, and Moniz and Salehi joined the talks to negotiate technical details. Zarif then flew to Brussels to meet with E.U. officials. The Iranian team returned to Switzerland for more talks with U.S. officials on March 17-18. 

March 26-April 2 – Iran and the P5+1 met in Lausanne, Switzerland in the final days before the deadline for a political framework. Kerry and Zarif held bilateral discussions, and negotiators from Britain, China, France, Russia, and Germany joined the talks on March 28.
 
April 2 – Zarif and E.U. foreign policy chief Federica Mogherini issued a joint statement announcing that Iran and the P5+1 had reached an understanding on key parameters for a comprehensive nuclear deal, with the final agreement to be drafted by June 30.
 
April 22-24 – Iranian Deputy Foreign Minister Abbas Araghchi and E.U. political director Helga Schmid met in Vienna on April 22. Under Secretary of State Wendy Sherman and deputy foreign minister from the P5+1 joined them later in the week to begin drafting a final agreement.
 
April 27 – Kerry and Zarif met on the sidelines of the 2015 Non-Proliferation of Nuclear Weapons Treaty Conference.
 
May 12-15 – Under Secretary of State Wendy Sherman and other deputy foreign ministers from Iran and the P5+1 met in Vienna to continue drafting a final nuclear deal.
 
May 27-30 – Deputy foreign ministers met in Vienna. Kerry and Zarif held talks in Geneva on May 30, their first meeting since the April 2 announcement.
 
June 3-4 - Deputy foreign ministers from Iran and the P5+1 met in Vienna, following a day of expert-level meetings.
 
June 10-14 – Deputy foreign ministers from Iran and the P5+1 held talks in Vienna.
 
June 17 – Deputy foreign ministers from Iran and the P5+1 held talks in Vienna.
 
June 22-26 – Deputy foreign ministers from Iran and the P5+1 held talks in Vienna.
 
June 28-29 – Kerry held meetings with Zarif, Mogherini, and the British, German, and French foreign ministers in Vienna. Zarif traveled to Tehran on June 28.
 
June 30 – Negotiators announced talks would be extended until July 7. Zarif returned to Vienna, and Russian Foreign Minister Sergei Lavrov met with Kerry in Vienna.
 
July 1 – Kerry and Zarif met one-on-one, joined later by U.S., E.U., and Iranian negotiators at the deputy foreign minister level.
 
July 2 – Foreign ministers from Iran and the P5+1 held a series of bilateral meetings. Talks also continued at the deputy foreign minister level. International Atomic Energy Agency (IAEA) director Yukiya Amano visited Rouhani and other officials in Tehran.
 
July 3-6 – Talks were held at the foreign minister, deputy foreign minister, and expert level. Kerry and Zarif held several bilateral meetings.
 
July 7-9 – Negotiators announced talks would be extended to July 10. Meetings were held at the foreign minister, deputy foreign minister, and expert level.
 
July 10-13 – On July 10, negotiators announced talks would be extended to July 13. Talks continued at the foreign minister, deputy foreign minister, and expert level.
 
July 14 – Foreign ministers from Iran and the P5+1 announced they had reached a final nuclear agreement.
 
July 20 – The U.N. Security Council unanimously adopted resolution 2231 endorsing the final deal. The deal and its annexes were also delivered to the U.S. Congress, beginning a 60-day review period.
 
Oct. 18 – Iran and the P5+1 marked the deal's Adoption Day. Iran began dismantling parts of its nuclear infrastructure, while the United States and European Union began preparations to lift certain sanctions.
 
Nov.18 – The IAEA released a report stating that Iran had removed 4,500 centrifuges at the Natanz and Fordo facilities. It still had to uninstall another 10,000 centrifuges to reach the target of 5,000.
 
Nov. 22 – The P5+1 issued a document outlining the redesign and reconstruction of Iran’s Arak nuclear reactor. It specified roles for each of the countries.
 
Dec. 2 – The IAEA concluded that Iran had worked on a “range of activities relevant to the development of a nuclear explosive device,” despite its denial of any work on a nuclear weapons program.  
 
Dec. 15 – The IAEA’s board decided to close the inquiry into the possible military dimensions of Iran’s nuclear program. The unanimous decision by the 35-nation group ended the 12-year probe while allowing inspectors to continue monitoring Tehran’s program.
 

2016 

Jan. 16 – Iran and the P5+1 marked the nuclear deal's Implementation Day after the IAEA confirmed that Iran has taken the necessary steps to start implementation of the nuclear deal. The United States, European Union, and United Nations lifted or suspended certain sanctions. Iran also regained access to the international financial system, repatriated billions of dollars in frozen assets abroad, and returned to the oil market.

Feb. 26 – The IAEA announced in a report that Iran briefly exceed the amount of heavy water it was allowed to have under the JCPOA by 0.9 tons. The U.N. nuclear watchdog also stated that Iran had rectified the issue by shipping 20 tons of heavy water one week after the limit was exceeded. Heavy water is used in certain types of nuclear reactors that can produce weapons-grade plutonium.

April 22 – The United States agreed to purchase 32 tons of heavy water from Iran. Under the JPCOA, Iran was required to keep its stocks of heavy water under 130 tons.

May 5 – AEOI Chairman Ali Akbar Salehi and IAEA Director General Yukiya Amano met in Tehran to discuss the implementation of the JCPAO.

May 27 – The IAEA released a report that stated Iran was in compliance with its obligations under the JCPOA.

July 12 – U.N. Secretary General Ban Ki-Moon released his first biannual report to the UN.. Security Council on the implementation of U.N. Security Council Resolution 2231 (2015), which endorsed the JCPOA, addressed JCPOA implementation, and reviewed other U.N. sanctions on Iran. The report found Iran was implementing its JCPOA obligations, but expressed concern over reports that Iran had violated arms transfer restrictions, ballistic missile activity restrictions, and restrictions on the travel of sanctioned individuals.

July 29 – Iran submitted a letter to the IAEA complaining about a leaked confidential document. The document, which the Associated Press reported on, indicated that certain key nuclear restrictions on Iran would be eased prior to the general 15-year expiration date of the deal. The IAEA denied that it had leaked the document.

Sept. 8 – The IAEA’s report found that Iran was in compliance with its obligations under the JCPOA.

Sept. 10 – Iran began construction on its second nuclear power plant with Russian help, the first such project since the final nuclear deal. The project in Bushehr included two plants and was slated to come online in 10 years.

Nov. 9 – The IAEA released a report that found Iran to be in general compliance with the JCPOA, although its heavy water stocks had exceeded the limit by 0.1 tons. Iran informed the IAEA that it was planning to ship five tons out of the country.

Dec. 13 – In response to the renewal of the Iran Sanctions Act by the United States, President Rouhani announced that Iran would begin work on nuclear-powered marine vessels. He said fuel production would be “in line with the development of a peaceful nuclear program of Iran.” But nuclear experts said that such fuel would likely require enrichment beyond the limits set by the JCPOA. Iran previously announced it was working on a nuclear-powered submarine in 2012.

Dec. 30 – U.N. Secretary General Ban Ki-Moon released his biannual report to the U.N. Security Council on the implementation of U.N. Security Council Resolution 2231 (2015). The report confirmed Iranian compliance with the JCPOA, but raised concerns about reports of Iranian arms transfer violations and the travel of sanctioned individuals, in violation of Resolution 2231.

2017

Jan. 16 – IAEA Director General Amano released a statement confirming that Iran had removed excess centrifuges and equipment from the Fordow Fuel Enrichment Plant as required under the JCPOA.

Jan. 28 – Iran's nuclear agency, the Atomic Energy Organization of Iran (AEOI), announced that it had injected uranium hexafluoride (UF6) into its most advanced centrifuge model, the IR-8, as part of research and development efforts. Under the JCPOA, Iran was allowed to test centrifuges with UF6 gas so long as the process does would not produce an accumulation of enriched uranium.

Feb. 24 – IAEA Director General Yukiya Amano released the IAEA’s quarterly verification report determining Iran had thus far been compliant in implementing its nuclear-related commitments under the JCPOA. The report noted Iran was voluntarily implementing the Additional Protocol, pending formalization, and had enriched 101.7 kg of uranium to 3.67 percent U-235.

May 17 – The Trump Administration certified Iranian compliance with the JCPOA and continued to waive nuclear-related sanctions. The administration, however, simultaneously announced new sanctions on Iran’s ballistic missile program.

June 2 – IAEA Director General Amano released the IAEA’s quarterly verification report, which found Iran to be in compliance with the JCPOA. The report noted Iran was voluntarily implementing the Additional Protocol, pending formalization.

June 20 – U.N. Secretary General Antonio Guterres released his biannual report to the U.N. Security Council on the implementation of Resolution 2231 (2015). The report confirmed Iranian compliance with the JCPOA, but raised concerns about the travel of sanctioned individuals, called on Iran to cease ballistic missile testing following the January launch of the Khorramshahr, and affirmed reports that weapons seized by France in the Indian Ocean were of Iranian origin.

July 17 – The Trump administration certified Iranian compliance with its JCPOA obligations. The administration simultaneously announced new sanctions targeting Iran’s ballistic missile program and other policies.

Aug. 31 – IAEA Director General Amano released the IAEA’s quarterly verification report, which found Iran to be in compliance with the JCPOA. The report noted Iran was voluntarily implementing the Additional Protocol, pending formalization.

Oct. 13 – President Trump decertified Iranian compliance with the nuclear agreement and outlined a new policy for countering the Islamic Republic. “I am directing my administration to work closely with Congress and our allies to address the deal’s many serious flaws so that the Iranian regime can never threaten the world with nuclear weapons,” he said. Trump authored the Treasury Department to further sanction the Islamic Revolutionary Guard Corps. He stopped short, however, of reimposing sanctions lifted as part of the JCPOA. The move created an opportunity for Congress to reintroduce sanctions, should it see fit.

Nov. 13 – IAEA Director General Amano released his verification report, which acknowledged Iranian compliance with the JCPOA. The report noted Iran was voluntarily implementing the Additional Protocol, pending formalization.

Dec. 8 – U.N. Secretary General Guterres released his biannual report to the U.N. Security Council on the implementation of UNSC Resolution 2231 (2015). The report confirmed Iranian compliance with the JCPOA but raised concern about U.S. participation following Trump’s October 13 decision to not recertify the deal. The report also raised concerns about suspected Iranian arms transfers, ballistic missile activities, and the travel of sanctioned individuals, in violation of Resolution 2231.

2018

Jan. 12 – President Trump waived nuclear-related sanctions against Iran for the third time, in compliance with U.S. obligations under the JCPOA. “I am waiving the application of certain nuclear sanctions, but only in order to secure our European allies’ agreement to fix the terrible flaws of the Iran nuclear deal,” he said. Trump also warned that he would withdraw from the deal if he judged that an agreement is not within reach. On the same day, the U.S. Treasury sanctioned 14 individuals, including Iran’s judiciary chief, for human rights abuses and supporting weapons proliferation.

Feb. 22 – IAEA Director General Amano released his verification report, which found that Iran had been complying with the JCPOA. The report noted Iran was voluntarily implementing the Additional Protocol, pending formalization. The report also said that Iran informed the IAEA of its intention to develop naval nuclear propulsion. The IAEA requested that Iran modify its Safeguards Agreement to provide the IAEA with preliminary facility designs. Iran had not replied to the request at the time of the report’s publishing.

April 30 – Israeli Prime Minister Netanyahu announced that Israel obtained some 100,000 “secret files that prove” Iran lied about never having a nuclear weapons program. Furthermore, he alleged that Tehran worked to “expand its nuclear weapons know-how for future use,” even after 2015 nuclear accord. Netanyahu presented maps, charts, photographs, and videos allegedly detailing Project Amad, whose goal was to design, produce and test nuclear weapons. The existence of Iran’s covert nuclear weapons program had been public knowledge for more than a decade.

May 8 – President Trump withdrew the United States from the JCPOA. The United States and European allies were unable to come to a compromise that would allay the administration’s concerns. “The fact is this was a horrible, one-sided deal that should have never, ever been made. It didn’t bring calm, it didn’t bring peace, and it never will,” Trump said in his address. Trump also announced his intention to reimpose sanctions on Iran that were lifted or suspended under the JCPOA. The United States gave businesses three to six months to comply with U.S. sanctions or face penalties.

Britain, France, Germany, and the European Union reaffirmed their commitment to the JCPOA soon after the announcement. Iranian officials condemned the U.S. move.

May 18 – In an effort to salvage the JCPOA, the European Commission announced four measures in response to the reimposition of U.S. sanctions on Iran. They included launching a process to activate the Blocking Statute, which forbids E.U. persons from complying with U.S. extraterritorial sanctions, allows companies to recover damages incurred by sanctions from the sanctioning party, and nullifies foreign court judgments in the European Union.

May 23 – Supreme Leader Ayatollah Ali Khamenei issued six conditions that must be met by Europe for Iran to remain in the nuclear deal. He demanded that Europe secure “a resolution against the U.S. violation” of U.N. Security Council Resolution 2231, which endorsed the Joint Comprehensive Plan of Action (JCPOA). Khamenei said Europe must promise to stop objecting to its missile testing and actions in the Middle East as well as to stand against U.S. sanctions. He also sought protection for oil sales and financial transactions with Iran. "If the Europeans linger over our demands, Iran has the right to resume its nuclear activities. When we see that the JCPOA was useless, one way forward is to restart those halted activities," Khamenei warned in an address to government officials.

May 25 – Representatives of the remaining parties to the JCPOA met with Iranian representatives for the first time after the U.S. withdrawal. They discussed ways to continue with the deal without the United States.

June 5 – Supreme Leader Khamenei ordered the AEOI to prepare for increased uranium enrichment if the JCPOA were to collapse. AEOI director Ali Akbar Salehi announced plans to increase production of uranium hexafluoride (UF6), the input for centrifuges producing enriched uranium. He also said that Iran would install a new generation of advanced centrifuges at Natanz if the JCPOA failed. On June 13, an AEOI spokesman added that Iran would also resume uranium enrichment at Fordow if withdrew from the JCPOA. The AEOI emphasized that it was still abiding by the JCPOA’s terms.

July 5 – Foreign ministers from the remaining signatories to the JCPOA met with Iranian Foreign Minister Zarif in Vienna to discuss ways to blunt the impact of U.S. sanctions on Iran. It was the first time the ministers had met since President Donald Trump pulled the United States out of the JCPOA on May 8. They failed to reach consensus on the content or timing of economic support to Iran.

Aug. 6 – The United States reimposed sanctions banning transactions with Iran in U.S. dollars. It also sanctioned trade in precious metals, aluminum, steel, aircraft, coal, carpets, and food. The European Union enacted a “blocking statute” to protect European firms engaged in business with Iran from U.S. legal action.

Aug. 30 – The IAEA released its quarterly report verifying that Iran remained in compliance with the JCPOA.

Sept. 25 – The remaining signatories of the JCPOA pledged to create a “Special Purpose Vehicle” (SPV) that would enable firms to make payments to Iran. The SPV would bypass U.S. sanctions by not using U.S. dollars.

Sept. 27 – In a speech to the United Nations, Israeli Prime Minister Benjamin Netanyahu said that Iran had concealed a warehouse for nuclear material located near Tehran. Iran denied the allegation.

Nov. 5 – U.S. sanctions prohibiting the purchase of Iranian oil went into effect. The United States granted waivers to eight countries—China, Greece, India, Italy, Japan, South Korea, Taiwan, and Turkey—allowing them to continue importing Iranian oil at reduced rates. On November 12, the IAEA quarterly report reaffirmed Iran’s compliance with the JCPOA.

Dec. 12 – Secretary of State Mike Pompeo demanded that the United Nations update Resolution 2231 to ban Iran from developing nuclear-capable ballistic missiles. The resolution only “called upon” Iran to refrain from missile work. 

2019

Jan. 13 – AEOI director Ali Akbar Salehi said that Iran was designing a modern process that would allow it to enrich uranium faster if Tehran left the JCPOA.

Jan. 29 – Director of National Intelligence Dan Coats told the Senate Intelligence Committee, “We do not believe Iran is currently undertaking activities we judge necessary to produce a nuclear device.” President Donald Trump tweeted in response, “The Intelligence people seem to be extremely passive and naive when it comes to the dangers of Iran. They are wrong!”

February 14 – Vice President Mike Pence demanded that the United States’ European allies leave the JCPOA. "The time has come for our European partners to withdraw from the Iran nuclear deal and join with us as we bring the economic and diplomatic pressure necessary to give the Iranian people, the region and the world, the peace, security and freedom they deserve," Pence said at an Iran-focused summit in Warsaw. German Chancellor Angela Merkel rejected the demand. On February 22, the IAEA’s quarterly report reaffirmed Iran’s compliance with the JCPOA.

March 22 – The United States sanctioned several individuals and entities involved in Iran’s past nuclear weapons program. A U.S. intelligence assessment had concluded that Iran’s nuclear weapons work stopped in 2003, but Trump Administration officials claimed that Tehran had kept its nuclear weapons team together in case Iran’s leaders decided to resume work.

April 22 – Secretary of State Pompeo announced that the United States would stop providing sanctions exemptions to eight countries that imported Iranian oil: India, China, Turkey, Italy, Greece, South Korea, Taiwan, and Japan. “We will continue to apply maximum pressure on the Iranian regime until its leaders change their destructive behavior, respect the rights of the Iranian people, and return to the negotiating table,” said Pompeo. He noted that oil sales accounted for up to 40 percent of Iran’s revenue. The Trump administration's stated goal was to bring Iranian exports down to zero.

May 3 – The United States sanctioned imports of enriched uranium from Iran. JCPOA signatory countries—notably Russia—had imported Iran’s enriched uranium to prevent Tehran’s supply from exceeding the JCPOA’s cap. The U.S. sanctions made it difficult for Iran to remain within JCPOA limits without halting its enrichment. The United States extended sanctions waivers that allowed foreign firms to work on reconfiguring Iranian reactors for civilian use and that allowed countries to provide enriched uranium fuel for civilian reactors in Bushehr and Tehran.

May 8 – President  Rouhani announced that Iran would stop complying with parts of the 2015 nuclear deal. In a televised speech to his cabinet, Rouhani said Iran would resume stockpiling excess uranium and heavy water used in its nuclear reactors. Rouhani warned that Iran would remove caps on uranium enrichment and resume work at the Arak nuclear facility if Iran’s oil and banking sectors are not protected from U.S. sanctions within 60 days. Rouhani expressed his impatience with the remaining parties to the JCPOA – Britain, China, France, Germany, and Russia. “We have given deadlines to JCPOA member states several times,” he said. "In simpler language, we felt that there was a need for surgery and the one-year-old painkillers were not enough; today's action is a surgical procedure to save the JCPOA, not to end it.”  

In a statement, Iran’s Supreme National Security Council criticized the international community for not meaningfully responding to U.S. efforts to undermine the JCPOA, enshrined in U.N. Security Council Resolution 2231. “Unfortunately, the goodwill and wise self-restraint of the Iranian people have remained unanswered, and no operational mechanisms have been set up to compensate for U.S. sanctions except for the issuance of political statements.” 

In a joint statement, the E.U. foreign policy chief and the foreign ministers of France, Germany and the United Kingdom reiterated their support for the JCPOA but also urged Iran to “implement its commitments under the JCPoA in full as it has done until now and to refrain from any escalatory steps.” 

May 27 – President Trump offered to negotiate a new nuclear deal with Iran and identified nuclear weapons as his priority. “It [Iran] has a chance to be a great country with the same leadership,” Trump said. “We aren’t looking for regime change - I just want to make that clear. We are looking for no nuclear weapons.”

June 11 – U.S. Ambassador Jackie Wolcott claimed that Iran was in breach of the JCPOA after a U.N. nuclear watchdog report found that it had installed 33 advanced centrifuges. The agreement allows Iran to test 30. “The United States calls on Iran to return to compliance without delay. We understand the JCPOA Joint Commission is treating this issue with the seriousness it deserves, and we urge the JCPOA participants to address this issue as soon as possible,” she told the governing board of the International Atomic Energy Agency. But Wolcott also said Washington was open to talks with Tehran toward reaching a more comprehensive agreement.  

July 1 – Iran breached the terms of the 2015 nuclear deal by exceeding limits on its stockpile of low-enriched uranium. Tehran is only allowed to store 300 kilograms of low-enriched uranium under the deal, negotiated by six major world powers. It is supposed to sell or exchange any surplus. "We told the Europeans that if more practical, mature and complete measures were taken, Iran's reduction (to its) commitments could be reversed. Otherwise, we will continue," said Foreign Ministry Spokesman Abbas Mousavi.

July 7 –  Iran announced that it would begin enriching uranium past the 3.67 percent limit set by the 2015 nuclear deal. “Within hours, the technical tasks will be done and enrichment above 3.67 percent will begin. We predict that the IAEA measurements early tomorrow morning will show that we have gone beyond 3.67 percent,” said Iran nuclear agency spokesman Behrouz Kamalvandi. President Rouhani had given European countries until July 7 to provide sanctions relief. 

July 8 – Iran began enriching uranium past the 3.67 percent mark specified by the 2015 nuclear agreement.  The Atomic Energy Organization of Iran announced that it was enriching uranium at 4.5 percent. The IAEA confirmed the breach after an inspection. Foreign Ministry spokesman Abbas Mousavi warned that Iran’s next step will be “harder, more steadfast and somehow stunning” if European countries do not find a way to bypass U.S. sanctions.  

July 10 – The United Sates accused Iran of committing “nuclear extortion” during an emergency meeting of the IAEA in Vienna. “There is no credible reason for Iran to expand its nuclear program, and there is no way to read this as anything other than a crude and transparent attempt to extort payments from the international community,” said U.S. Ambassador to the International Organizations in Vienna. President Trump vowed that the United States would respond with additional sanctions against Tehran. 

July 14 – President Hassan Rouhani said Iran was ready to hold discussions with the United States if the Trump administration agreed to end crippling sanctions and return to the 2015 nuclear deal. “We have always believed in talks ... if they lift sanctions, end the imposed economic pressure and return to the deal, we are ready to hold talks with America today, right now and anywhere,” said Rouhani on state television. 

July 18 – Iranian Foreign Minister Mohammad Javad Zarif offered to immediately accept more intrusive international inspections of Tehran’s nuclear facilities if the United States agreed to lift sanctions. He told a group of reporters that Iran’s parliament would fast track the Additional Protocol of the IAEA that would allow extensive monitoring of its nuclear program. “If Trump wants more for more, we can ratify the Additional Protocol and he can lift the sanctions he set,” Zarif said. "He has said that he will take any measure to Congress – fine. Lift the sanctions and you’ll have the Additional Protocol sooner than 2023.” The 2015 nuclear deal originally required Iran's parliament to ratify the clause by October 2023.  

July 28 – The remaining signatories of the JCPOA—Britain, France, Germany, Russia, China, and Iran—met in Vienna to salvage the 2015 nuclear deal. "The atmosphere was constructive. Discussions were good. I cannot say that we resolved everything, I can say there are lots of commitments," said Iranian Deputy Foreign Minister Seyed Abbas Araghchi.  

Fu Cong, the representative of the Chinese delegation, said that all parties “strongly opposed” the U.S. decision to leave the deal and impose unilateral sanctions on Tehran. The Europeans urged Iran to fully comply with the nuclear deal, and all parties agreed to hold a higher-level meeting with foreign ministers in the future. No date was announced at the summit. 

Ali Akbar Salehi, the head of Iran’s Atomic Energy Organization, announced Tehran would restart activities at the Arak heavy water nuclear reactor. Salehi added that Iran had enriched 24,000 kilograms of uranium since 2015. The nuclear deal restricted Iran to a 300-kilogram stockpile. 

July 31 – Foreign Minister Mohammad Javad Zarif warned that Iran would “take the next step” in cutting commitments to the JCPOA if Europe failed to shield Tehran from U.S. sanctions. Zarif added that European countries should guarantee the sale of Iranian oil.  

The U.S. State Department renewed five sanctions waivers permitting foreign firms to work on Iran’s civil nuclear program without penalties. The waivers, which were renewed for an additional 90 days, specifically permitted European, Russian, and Chinese companies to continue civil nuclear projects at Iranian nuclear facilities.  

Aug. 12 – Foreign Minister Zarif reaffirmed Iran’s commitment to the 2015 nuclear deal. “It wasn't the best deal for everybody because you cannot have the perfect deal. There is no perfect deal," he said. "And if President Trump is given correct advice, he will be able to basically accept the reality that this is the best deal possible and we can move forward." 

Aug. 19 – Ali Shamkhani, the secretary of Iran’s Supreme National Security Council, said it was a mistake for Iran to sign the 2015 nuclear deal. He added that the U.S. “maximum pressure” campaign would not force concessions from Tehran. "The sanctions campaign is not for negotiation, it's for making us surrender," said Shamkhani. "As long as this approach is taken by the United States, Iran will never ever seek negotiations."

Aug. 22 – Iran said it was ready to negotiate with France over proposals to salvage the 2015 nuclear deal. French President Emmanuel Macron said Paris was willing to reduce sanctions or develop a compensation mechanism if Iran agreed to return to the deal. “There are proposals on the table, both from the French and the Iranian side, and we are going to work on those proposals tomorrow,” said Iranian Foreign Minister Mohammad Javad Zarif.  

Aug. 30 – An IAEA report revealed that Iran had again breached the 2015 nuclear deal by increasing its stock of enriched uranium and refining it to a greater purity. The assessment said Iran had accumulated 241.6 kg of enriched uranium and was enriching at up to 4.5 percent, up from 202.8-kg at 3.67 percent in an IAEA report from July. 

Sept. 2 – Iran threatened to further reduce its commitments to the 2015 nuclear deal by Sept. 6 if the European Union did not find a way to ease U.S. sanctions. Tehran said it would take measures such as resuming uranium enrichment at 20 percent, which it said it could do within one to two days. “The third step has been designed and will be stronger than the first and second steps to create balance between Iran’s rights and commitments to the JCPOA,” said foreign ministry’s spokesman Abbas Mousavi.  

Sept. 4 – Iranian President Hassan Rouhani announced that Tehran would give Europe another two months to salvage the 2015 nuclear deal before it took further steps to reduce its commitments. Iran originally set the deadline as Sept. 6.  

Rouhani said Iran would begin developing centrifuges for faster uranium enrichment at nuclear power plants. “From Friday, we will witness research and development on different kinds of centrifuges and new centrifuges and also whatever is needed for enriching uranium in an accelerated way,” Rouhani said. “All limitations on our Research and Development will be lifted on Friday.” 

Sept. 7 – Iran announced that it had begun using an array of 20 IR-6 centrifuges and an array of 20 IR-4 centrifuges to enrich uranium. The IR-6 and IR-4 centrifuges are 10 and five times, respectively, as fast as the IR-1s. Under the JCPOA, Iran was only allowed to use 5,060 IR-1s. 

Sept. 8 – Two diplomatic sources told Reuters that the IAEA found uranium traces at a site that Israeli Prime Minister Netanyahu alleged was a “secret atomic warehouse.” The uranium was not highly enriched but called Tehran’s transparency into question. U.S. National Security Advisor John Bolton demanded a report as soon as possible.

Sept. 9 – Prime Minister Netanyahu alleged that Iran conducted experiments relating to nuclear weapons development at a site near the city of Abadeh. “When Iran realized that we uncovered the site, here’s what they did,” he said in televised remarks, showing a photograph of the site from a month later. “They destroyed the site. They just wiped it out.”

On Twitter, Foreign Minister Zarif accused Netanyahu of lying and posted a picture of a newspaper story discussing Israel’s undeclared nuclear arsenal in Dimona. 

Sept. 25 – The IAEA found that Iran had breached the JCPOA again by using advanced centrifuges to enrich uranium. The U.N. watchdog “verified that all of the (centrifuge) cascades already installed in R&D lines 2 and 3 ... were accumulating, or had been prepared to accumulate, enriched uranium,” according to a new report. The JCPOA only allowed Iran to use some 5,000 of its first-generation IR-1 centrifuges to enrich uranium. Advanced centrifuges were supposed to only be used in small numbers for research purposes.

Nov. 4 – Iran began operating 30 new IR-6 centrifuges, doubling its number of the advanced machines. The chief of the Atomic Energy Organization of Iran, Ali Akbar Salehi, said Iran was operating 60 of the centrifuges, which are some 10 times more efficient than the IR-1s allowed under the JCPOA. The announcement coincided with the 40th anniversary of the takeover of the U.S. embassy in Tehran by students. 

Salehi said that Iran went from producing about 450 grams (1 pound) of low-enriched uranium a day to 5 kilograms (11 pounds). He said Iran’s stockpile had grown beyond 500 kilograms (1,102 pounds). The JCPOA had limited Iran’s stockpile to 300 kilograms (661 pounds)

                        

Garrett Nada, Eli Pollock, Cameron Glenn, Daniel Schnur, and John Caves also contributed to this timeline.