Part I: Iran in Syria

Since mid-2011, Iran’s military intervention in Syria has grown steadily. By 2015, at least eight Islamic Revolutionary Guards Corps (IRGC) generals had been killed in Syria. As of February 2018, Iranian forces and their proxies were deployed in nearly 40 facilities—including headquarters, logistical nodes, drone control rooms, training centers and other sites, not including forward positions. Tehran has tapped a wide variety of forces to fight in the Levant, including the IRGC and the conventional army. Iranian presence has varied from the high hundreds to the low thousands. Qassem Soleimani, the IRGC commander of the elite Qods Force, has been routinely photographed with militias for several years. By April 2018, more than 500 Revolutionary Guards had been killed.


The Islamic Republic has also mobilized some 20,000 fighters from Lebanon, Iraq, Afghanistan and Pakistan to fight in Syria. One tally estimated that more than 2,300 foreign Shiite fighters—many under Iran’s control—had been killed, including more than 1,200 Lebanese by April 2018. Another estimate claimed Hezbollah’s losses exceeded 2,000, with another 7,000 injured.

Iran’s military presence in Syria has attracted increasing scrutiny from both regional players and Western powers. Its forces and bases have also been growing targets of Israeli airstrikes, including in February and April 2018.

Syria’s use of chemical weapons –both proven and alleged—has generated a policy quandary for Tehran. Iran was repeatedly the victim of chemical weapons attacks by the Iraqi regime of President Saddam Hussein during the 1980-88 Gulf war. But in 2018, Iran dismissed Western allegations that President Bashar al Assad ordered the use of chemical weapons against civilians in Douma, a rebel-held suburb of Damascus. “Such allegations by the U.S. and some other Western countries reveal a new plot against the Syrian government and people,” said Iranian Foreign Ministry Spokesman Bahram Ghassemi. “This is an excuse for military action against Syrians.” The Syrian American Medical Society reported that more than 500 people showed signs of exposure to a chemical agent, including “respiratory distress, central cyanosis, excessive oral foaming, corneal burns, and the emission of chlorine-like odor.”


Foreign Minister Mohammad Javad Zarif


Known Facts:

  • Iran has long had ties with Syria, dating back to the 1979 revolution, but increased its aid, arms and military advice after the civil war erupted in 2011.
  • Its presence has grown from advising and training to fighting in major battles, notably in Aleppo.
  • Both the Revolutionary Guards’ elite Qods Force and Iran’s conventional Artesh military forces have deployed in Syria.
  • Iran supplemented its own forces with thousands of Hezbollah fighters from Lebanon as well as primarily Shiite recruits from Afghanistan, Pakistan and Iraq.
  • At least 2,000 Hezbollah fighters have died in Syria, with another 10,000 injured, according to some estimates.
  • By 2015, at least eight generals had been killed in Syria.
  • The United States has sanctioned Soleimani since May 2011 for his complicity in Syria repression and human rights abuses. In June 2011, the U.S. Treasury Department sanctioned Iran Air for transporting IRGC equipment—including missile and rocket components—to Syria.
  • Iran ran a command-and-control center at Syria’s Tiyas, or T-4, base, which was targeted in Israeli airstrikes in February and April 2018.




Syria has become a battlefield for tensions between Iran and Israel that for decades had played out in neighboring Lebanon. Since 2011, many of the some 100 Israeli airstrikes have targeted Iranian military positions as well as weapons caches and transport convoys to prevent Iran from delivering advanced rockets and missiles to Hezbollah through Syria. In 2015, an Israeli airstrike killed Mohammad Ali Allah-Dadi, an IRGC general, and six Hezbollah fighters in Syria’s Golan Heights.

“The goal now is to prevent Iran and Hezbollah from crossing Israeli red lines—basically so they have no presence close to the border with Israel and no activities that harm the interests of Israel,” Shlomo Brom, a retired brigadier general and former director of Strategic Planning for the Israel Defense Forces told The New Yorker in April 2018.

The T-4 command center has been a key point of concern for Israel. On February 10, an Israeli combat helicopter intercepted an Iranian drone that crossed the Syria-Israel border. IDF spokesman Lt. Col. Jonathan Conricus told CNN that Israel tracked the unmanned craft from its launch from the Iranian T-4 command center near Palmyra, Syria. Eight Israeli jets attacked Iranian targets in Syria about an hour later, one of which was hit by Syrian missiles, forcing the pilot and navigator to eject. Israeli air force Brig. Gen. Tomer Bar said it was the “most significant attack” of its kind against Syria since the 1982 Lebanon war.


Tensions deepened after an alleged Israeli airstrike in Syria on April 9, 2018, that killed at least 14 people, including seven Iranian military advisers. Russia and Syria accused Israel of sending two F-15 jets to attack the T-4 air field near Palmyra. Moscow said that Syrian air defenses shot down five of eight missiles. Hours later, Israel’s foreign ministry released a statement condemning Syria’s use of chemical weapons that did claim responsibility for the airstrike:

“Israel strongly condemns the chemical weapons strike carried out by Syria on April 7…The Syrian regime continues to perpetrate crimes against humanity in using these outlawed weapons. The latest attack joins a long series of similar attacks using chemical weapons perpetrated by the regime since Assad undertook to disarm from such weapons. The attack shows clearly that Syria continues to possess lethal chemical weapons capabilities and even to manufacture new ones. In so doing Syria is grossly violating its obligations and the decisions of the international community in this matter.”

Iran released the names of the advisers, including a colonel in the drone program, and repatriated the bodies on April 10. The strike on the military base was “Israel’s crime” and will “not go unanswered,” warned Foreign Policy Adviser to the Supreme Leader, Ali Akbar Velayati warned on April 10 during a visit to Damascus. “The defenders of shrines will continue to stand by the Syrian government and people against the enemies of the Islamic community, particularly the Zionist regime and its masters, in this country.” Velayati was referring to dozens of Shiite holy sites in Syria.



On April 11, Israeli Defense Minister Avigdor Lieberman said Israel cannot allow Iran to establishment a permanent military presence in Syria. “No matter what the price, we will not allow Iran to have a permanent [military] foothold in Syria. We have no other choice,” he warned. Prime Minister Benjamin Netanyahu alluded to Israel’s actions in Syria in a speech marking Holocaust Remembrance Day. “We are preventing Iranian activity in Syria. These are not just words,” he said on April 11. “I have a message to the Iranian rulers — do not test the determination of the State of Israel.”


Garrett Nada is the managing editor of "The Iran Primer" and "The Islamists" websites at the U.S. Institute of Peace. 

Click here for a timeline of Iran's intervention in Syria. 


Homepage photo credit: Syrian President Bashar Assad and Supreme Leader Ali Khamenei via and Facebook
Some of the information in this article was originally published on April 10, 2018.