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MSCI Advisory

2020-001-Persian Gulf, Strait of Hormuz, Gulf of Oman, Arabian Sea, Red Sea, Gulf of Aden, and Indian Ocean-Threats to Commercial Vessels by Iran and its Proxies


This revised advisory cancels U.S. Maritime Advisory 2019-012

1. References: U.S. Maritime Alerts 2020-001A and 2020-001B.

2. Issue: Multiple maritime threats have been reported in the geographic areas described above. 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. Vessels have also reported bridge-to-bridge communications from unknown entities falsely claiming to be U.S. or coalition warships.

In addition to the maritime incidents highlighted in previous U.S. Maritime Alerts and Advisories, the following incidents have occurred in this region:

- September 14, 2019: Attack on Kingdom of Saudi Arabia oil facilities

- January 2, 2020: U.S. military took decisive defensive action to protect U.S. personnel abroad

- January 7, 2020: Iran attacked U.S. forces in Iraq with missiles.

The U.S. Department of Homeland Security's Cybersecurity and Infrastructure Security Agency (CISA) also issued Alert AA20-006A (available at on January 6, 2020, regarding the potential for an Iranian cyber response. In part, the CISA alert notes "Iran's historic use of cyber offensive activities to retaliate against perceived harm", chronicles Iranian cyber activity, and provides recommended actions to mitigate vulnerabilities. Vessel owners and operators are reminded to report suspected maritime cybersecurity incidents as required in the USCG Policy Letter at

The U.S. government is continually assessing the maritime security situation in the region to safeguard freedom of navigation; ensure the free flow of commerce; and protect U.S. vessels, personnel, and interests.

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 (except in extraordinary circumstances, consistent with provisions of the Convention on Safety of Life at Sea), and monitor VHF Channel 16.

a) To afford best protection in the region, U.S. flagged commercial vessels are also advised to:

- For the Red Sea. Arabian Sea, the Gulf of Oman, and the Persian Gulf: Simultaneously register with both the United Kingdom Maritime Trade Office (UKMTO) and the U.S. Naval Forces Central Command Naval Cooperation and Guidance for Shipping (NAVCENT NCAGS) Watch 24 hours prior to entering the Indian Ocean Voluntary Reporting Area by sending UKMTO and NCAGS, via a single e-mail, 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). Include the estimated times of arrival at the Suez Canal, Bab el Mandeb Strait (BAM), and Strait of Hormuz (SoH) in line 10 of the report, and add a line 14 for comments as needed (e.g., speed restrictions or other constraints, anticipated time of entering/exiting the SoH Traffic Separation Scheme; an outline of the navigation plan for operating in the SoH and Persian Gulf, etc.).

- NAVCENT NCAGS has the latest information on the dynamic maritime security threats and operational environment in this region. U.S. vessels are advised to exercise caution, coordinate vessel voyage planning for transits in the region with NCAGS, and follow NCAGS’s recommendations and guidance whenever possible.

- 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 NAVCENT 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, as reflected in the Law of the Sea Convention, 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 offers industry issued best practices, including BMP5, 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 NAVCENT 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:

b) NAVCENT NCAGS: or +973-1785-2983 or +973-1785-0084.

c) UKMTO: or +44 (0) 2392 222060. UKMTO advisories and warnings are available at

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 Supplemental information may also be found on the MARAD Office of Maritime Security website at:

5. Cancellation of Prior Advisories: This message supersedes and cancels U.S. Maritime Advisory 2019-012. This advisory will automatically expire on July 11, 2020.

For more information about U.S. Maritime Alerts and Advisories, including subscription details, please visit