On August 7, the U.S. Department of Transportation’s Maritime Administration warned commercial vessels of Iranian threats in the Persian Gulf, Strait of Hormuz, and Gulf of Oman. The advisory said vessels could encounter “GPS interference, bridge-to-bridge communications spoofing, and/or other communications jamming with little to no warning.” Iran had used GPS interference on at least two occasions since May 2019, according to the advisory.
Tehran installed jamming devices on Abu Musa Island near the Strait of Hormuz, a Pentagon official told CNN. The jammers disrupted the navigation systems on civilian ships, which caused them to drift into Iranian waters. Iran disguised IRGC and Iranian naval vessels as merchant ships by “spoofing” their automatic identification codes, the official added. The following is a statement from U.S. Central Command and the Department of Transportation advisory.
U.S. Central Command Statement
Due to the heightened regional tensions, the potential for miscalculation or misidentification could lead to aggressive actions against vessels belonging to U.S., allied and coalition partners operating in the Arabian Gulf, Strait of Hormuz, and Gulf of Oman. Vessels have reported GPS interference, bridge-to-bridge communications spoofing, and/or other communications jamming with little to no warning.
The U.S. remains committed to working with allies and regional partners to safeguard the freedom of navigation, the free flow of commerce, and the protection of U.S. vessels and personnel in this region.
Department of Transportation Advisory
1. References: U.S. Maritime Alerts 2019-004A, 2019-003A, 2019-002A, and 2019-001A.
2. Issue: Heightened military activity and increased political tensions in this region continue to pose serious threats to commercial vessels. Associated with these threats is a potential for miscalculation or misidentification that could lead to aggressive actions. Vessels operating in the Persian Gulf, Strait of Hormuz, and Gulf of Oman may also encounter GPS interference, bridge-to-bridge communications spoofing, and/or other communications jamming with little to no warning.
Since May 2019, the following maritime incidents have occurred in this region:
- Six attacks against commercial vessels (see U.S. Maritime Alerts 2019-002A and 2019-003A);
- Shoot-down of U.S. Navy remotely piloted aircraft over international waters;
- Attempted at-sea interdiction of Isle of Man-flagged M/V BRITISH HERITAGE;
- Seizure of ex-Panama-flagged M/V RIAH;
- Seizure of U.K.-flagged M/V STENA IMPERO (see U.S. Maritime Alert 2019-004A); and
- Detention and subsequent release of Liberian-flagged M/V MESDAR (see U.S. Maritime Alert 2019-004A).
In at least two of these incidents, vessels reported GPS interference. One vessel reportedly shut off its Automatic Identification System (AIS) before it was seized, complicating response efforts. Vessels have also reported spoofed bridge-to-bridge communications from unknown entities falsely claiming to be U.S. or coalition warships.
The United States is committed to safeguarding freedom of navigation, the free flow of commerce, and the protection of U.S. vessels and personnel in this region.
3. Guidance: The international community, including the United States, continues maritime security operations within this region. Vessels operating in this area are advised to review security measures, ensure AIS is transmitting at all times, and monitor VHF Channel 16.
a) To afford best protection in the region, U.S. flagged commercial vessels are encouraged to:
- Simultaneously register with both the United Kingdom Maritime Trade Office (UKMTO) and U.S. Fifth Fleet Naval Cooperation and Guidance for Shipping (NCAGS) Watch when entering the Indian Ocean Voluntary Reporting Area (VRA) by e-mailing them the Initial Report from Annex D of Best Management Practices to Deter Piracy and Enhance Maritime Safety in the Red Sea, Gulf of Aden, Indian Ocean and the Arabian Sea (BMP5).
- Provide transit plans for the Strait of Hormuz (SoH) and Persian Gulf (PG) to UKMTO and U.S. Fifth Fleet NCAGS via a single e-mail, including the time of entering/exiting the SoH Traffic Separation Scheme, an outline of the navigation plan for operating in the SoH and PG, and speed restrictions or other constraints.
- In the event of any incident or suspicious activity, call UKMTO or the U.S. Fifth Fleet Battle Watch and activate the Ship Security Alert System immediately.
- Answer all VHF calls from coalition navies.
- Utilize other reports included in Annex D of BMP5 as necessary, including both UKMTO and Fifth Fleet NCAGS on each of these reports.
b) All vessels should be aware that U.S. and other coalition naval forces may conduct maritime awareness calls, queries, and approaches to ensure the safety of vessels transiting the Persian Gulf, Strait of Hormuz, Gulf of Oman, and Arabian Sea. If a U.S. flag commercial vessel suspects it is being hailed from a source falsely claiming to be a U.S. or coalition naval vessel, the U.S. Fifth Fleet Battle Watch should be immediately informed.
c) If hailed by Iranian forces, U.S. flag commercial vessels should provide vessel name, flag state, and affirm that they are proceeding in accordance with international law as reflected in the Law of the Sea Convention. The master should immediately inform the U.S. Fifth Fleet Battle Watch.
d) If Iranian forces seek to board a U.S. flag commercial vessel navigating these waters, the ship’s Master should, if the safety of the ship and crew would not be compromised, decline permission to board, noting that the vessel is proceeding in accordance with international law, and immediately inform the U.S. Fifth Fleet Battle Watch.
e) If Iranian forces board a U.S. flagged commercial vessel, the vessel should immediately contact the U.S. Fifth Fleet Battle Watch. The crew should not forcibly resist the boarding party. Refraining from forcible resistance does not imply consent or agreement to that boarding.
f) The Maritime Global Security website at https://www.maritimeglobalsecurity.org/ offers industry issued best practices, including BMP5, and guidance to mariners by geographic region and provides contact and subscription information for regional maritime security reporting centers.
g) Vessels operating in this area are advised to establish contact with both UKMTO and the U.S. Fifth Fleet NCAGS Watch, and to include both on all update or incident report emails, as detailed above. By including both as addressees on each email, awareness will be enhanced without creating an additional reporting burden.
4. Contact Information:
a) Fifth Fleet Battle Watch: + 973-1785-3879, and email details to: CUSNC.BWC@ME.NAVY.MIL.
b) Fifth Fleet NCAGS: CUSNC.NCAGS_BW@ME.NAVY.MIL or +973-3904-9583 or +973-1785-0084.
d) U.S. Coast Guard: Per 33 CFR 101.305, all suspicious activities, breaches of security, and transportation security incident events must also be reported to the U.S. Coast Guard National Response Center at +1-800-424-8802.
e) For maritime industry questions about this advisory, contact GMCC@uscg.mil. Supplemental information may also be found on the MARAD Office of Maritime Security website at: https://go.usa.gov/xUKsb.
5. Cancellation of Prior Advisories: This message supersedes and cancels and U.S. Maritime Advisories 2019-004 and 2019-008. This advisory will automatically expire on February 3, 2020.