(WASHINGTON) — Regional conflict, military activity, terrorist attacks and piracy pose significant threats to commercial vessels operating in the following geographic areas: Southern Red Sea, Bab el Mandeb Strait, Gulf of Aden, Indian Ocean, Somali Basin, Arabian Sea, Gulf of Oman, Strait of Hormuz and Persian Gulf.
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. The recent standup of Operation Prosperity Guardian and EUNAVFOR Operation Aspides are examples of U.S. and international cooperative maritime security operations within this region.
The following are currently deemed to be the most pressing threats to U.S.-flagged and U.S.-affiliated commercial vessels throughout this region.
Guidance
Houthi hostile actions: Commercial vessels transiting the Southern Red Sea, Bab el Mandeb Strait, and Gulf of Aden continue to be at an elevated risk of terrorism and other hostile actions from the Houthis. Hostile actions include one-way unmanned aerial vehicle (UAV) attacks; unmanned surface vehicle (USV) attacks; ballistic and cruise missile attacks; small arms fire from small boats; explosive boat attacks; and illegal boardings, detentions, and/or seizures.
There have been at least 53 separate Houthi attacks on commercial vessels and one Houthi seizure of a commercial vessel in these areas, affecting over 55 nations since Nov. 19. Entities claiming to be Yemeni authorities have also attempted to divert commercial vessels operating in these regions from their course. These threats pose both direct and collateral risks to commercial vessels transiting in international shipping lanes, or otherwise operating in these areas.
Since January, one vessel was sunk by the Houthis in the Bab el Mandeb Strait and one vessel was struck by the Houthis in the Gulf of Aden, resulting in loss of life and forcing the crew to abandon the vessel. Both incidents resulted in the issuance of navigation warnings. Commercial vessels operating in these areas should be vigilant for hazards to navigation caused by vessels being struck by the Houthis and should be aware of all current navigation warnings.
U.S.-flagged commercial vessels transiting the Southern Red Sea, Bab el Mandeb Strait, and Gulf of Aden with automatic identification system (AIS) transponders on are at increased risk of targeting by adversarial actors. U.S.-flagged commercial vessels operating in these areas are strongly advised to turn off their AIS transponders, unless vessel masters believe that doing so would compromise the safety of the vessel.
The International Convention for the Safety of Life at Sea (SOLAS), Chapter V, regulation 19.2.4, and IMO Assembly Resolution A 29/Res.1106 permit vessel masters to turn AIS off if they “believe that the continual operation of AIS might compromise the safety or security of their ship, or where security incidents are imminent.” See also 33 CFR § 164.46(d)(2)(v).
While vessels have been attacked by the Houthis while AIS transponders were on and while off, turning AIS off makes it more difficult to track and accurately target a vessel. Vessel data, including AIS tracking data, is available from a variety of commercial web-based companies. Adherence to all flag state and international requirements and guidance regarding operation of AIS, and the safe navigation of the vessel, remains the responsibility of individual companies and vessel Masters. Limiting AIS data to only the mandatory fields and omitting the vessel’s next port of call well before entering the Red Sea and Gulf of Aden should also be considered.
U.S.-flagged commercial vessels operating in these areas are advised to remain as far as possible from Yemen’s coastline without compromising navigational safety. Crewmembers should be especially vigilant when at anchor, operating in restricted maneuvering conditions, loitering, or proceeding at slow speeds.
U.S.-flagged commercial vessels should coordinate voyage planning with U.S. Naval Forces Central Command (NAVCENT) Naval Cooperation and Guidance for Shipping (NCAGS) and consider their recommendations and guidance whenever possible. NAVCENT NCAGS stands a 24-hour watch and has the latest information on the current maritime security threats and the operational environment in this region.
The route taken through these areas and the timing of the transit remain at the discretion of individual companies and vessel masters. As web-based providers of commercial vessel data can include information beyond AIS tracking such as prior vessel tracks, planned routes, waypoints, and speeds should not be duplicated from prior voyages, when possible. Transiting these areas during hours of darkness may frustrate efforts to target vessels.
U.S.-flagged commercial vessels are advised to provide hourly positional email updates to the NAVCENT NCAGS detachment when transiting these areas.
Maritime operators are advised to alert their crews to the fact that all electronic signals from their vessels pose a risk to maritime operations and are strongly advised to secure WiFi routers while underway in these areas when feasible.
Web- and app-based providers of commercial vessel data could allow access to a vessel’s ownership and management information, which could be exploited by adversarial actors.
A missile strike on a Marshall Islands-flagged commercial tanker in the Gulf of Aden on Jan. 26 resulted in a significant onboard fire. U.S.-flagged commercial vessels carrying flammable, explosive, or otherwise hazardous cargoes are strongly advised to reconsider transit through these areas. However, if planning voyages through these areas, vessels should take all prudent safety precautions, including thoroughly preparing for emergency responses, and consider carriage of additional safety and damage control preparedness supplies and equipment.
If hailed on VHF by the Houthis, or entities claiming to be Yemeni authorities, and instructed to divert from their course, U.S.-flagged commercial vessels should ignore the VHF call and continue their passage if safe to do so. U.S.-flagged commercial vessels that encounter this tactic are advised not to follow Houthi direction to divert course, as doing so may enhance the ability of the Houthis to accurately target vessels. U.S.-flagged commercial vessels are advised to update the NAVCENT NCAGS detachment when this occurs.
If the Houthis seek to board a U.S.-flagged commercial vessel in these areas, the vessel’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.
When combined with evasive maneuvering, vessels transiting these areas with armed security details onboard have successfully deterred boarding by individuals in approaching small craft. The decision whether to embark a contracted armed security detail and assessment of associated risks is the responsibility of individual companies and vessel Masters, who are responsible for establishing use of force guidance and pre-planned responses for vessels carrying contracted armed security details.
If Houthis board a U.S.-flagged commercial vessel without a contracted armed security detail onboard, the crew should not forcibly resist the boarding party. Refraining from forcible resistance does not imply consent or agreement to that boarding.
When operating in these waters, U.S.-flagged commercial vessels should always maintain a proper, vigilant lookout by employing all suitable means in the prevailing circumstances and conditions. This includes incorporating additional lookouts to ensure a comprehensive assessment of the situation. See 1972 COLREGS, Rule 5.
If U.S.-flagged commercial vessels observe or hear a suspected UAV or missile or observe a small boat approaching with apparent hostile intent, crewmembers not needed for the safe navigation and operation of the vessel should be relocated to a safe space until the threat has passed. Additional precautions should be taken to ensure small boats are kept at a safe distance whenever possible.
In addition to U.S. maritime alerts and this advisory, interim industry transit advice for the Southern Red Sea and Gulf of Aden is being distributed by Combined Maritime Forces (CMF). CMF guidance messages are available on the Maritime Global Security website.
A new Red Sea/Gulf of Aden Joint Maritime Information Center (JMIC), which is a
collaborative effort between Combined Maritime Forces, the Singapore Navy’s Information Fusion Center, the Royal Netherlands Navy’s NCAGS, the U.S. Navy Fifth Fleet’s NCAGS, and others, is now providing weekly dashboard and incident-specific notes regarding threats and incidents in this region.
Iranian illegal boarding/detention/seizure: Commercial vessels transiting the Persian Gulf, Strait of Hormuz, Gulf of Oman, and Arabian Sea are at risk of being illegally and
detained or seized by Iranian forces. Recent incidents include the April 2023 Iranian seizure of a Marshall Islands-flagged vessel in the Gulf of Oman, the May 2023 Iranian seizure of a Panama-flagged vessel in the Strait of Hormuz, and the January 2024 Iranian seizure of a Marshall Islands-flagged vessel in the Arabian Sea.
Iranian forces attempted to seize one Marshall Islands-flagged vessel and one Bahamas-flagged vessel in the Gulf of Oman during July 2023, but were prevented from doing so by U.S. naval forces. Iranian forces have utilized small boats and helicopters during boarding operations and have attempted to force commercial vessels into Iranian territorial waters.
If hailed by Iranian forces, U.S.-flagged commercial vessels should provide vessel name and flag state and affirm that they are proceeding in accordance with international law as reflected in the Law of the Sea Convention.
If Iranian forces seek to board a U.S.-flagged commercial vessel navigating these waters, the vessel’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.
If Iranian forces board a U.S.-flagged commercial vessel, the crew should not forcibly resist the boarding party. Refraining from forcible resistance does not imply consent or agreement to that boarding.
It is recommended that vessels in the Persian Gulf remain as far as possible from Iran’s territorial sea without compromising navigational safety. When transiting eastbound in the Strait of Hormuz, it is recommended that vessels transit close to Oman’s territorial sea.
Industry transit advice for the Persian Gulf, Strait of Hormuz, and Gulf of Oman was issued on Nov. 9 and can be found on the Maritime Global Security website.
Piracy and armed robbery against ships: Recent cases of piracy pose a threat to commercial vessels operating in the Gulf of Aden, Arabian Sea, Somali Basin, and Indian Ocean. Since November, there have been four boarding/hijacking incidents, representing the first such attacks against commercial shipping in the region since March 2017.
Pirates may utilize captured fishing vessels as motherships to target vessels operating hundreds of miles from the coast of Somalia. In November, one Liberian-flagged vessel was boarded in the Gulf of Aden; in December, one Malta-flagged vessel was hijacked in the Arabian Sea; and in January, one Liberia-flagged bulk carrier was boarded in the Indian Ocean. Specific case details are available on the Office of Naval Intelligence’s weekly “Worldwide Threat to Shipping” product.
The Best Management Practices to Deter Piracy and Enhance Maritime Security in the Red Sea, Gulf of Aden, Indian Ocean and Arabian Sea (BMP5), and Maritime Global Security website should be consulted prior to operating in those geographic waters.
Transit by yachts and privately owned sailing vessels through these waters is hazardous and may result in capture. The U.S. government advises against all operation of yachts and pleasure craft in these areas.
American citizens abroad should inform the nearest U.S. embassy or consulate of their plans to transit the area and/or update their information via the Smart Traveler Enrollment Program (STEP). Yachting guidance can be found at: https://onshore.mschoa.org/reference-documents/advice-for-sailing-vessels.
UAVs: Outside of the Southern Red Sea, Bab el Mandeb Strait, and Gulf of Aden, UAV attacks also pose a threat to commercial vessels in the Persian Gulf, Strait of Hormuz, Gulf of Oman, and Arabian Sea. The most recent attacks were on a Malta-flagged vessel in the Arabian Sea in November, and on a Liberian-flagged vessel in the Arabian Sea in December.
If U.S.-flagged commercial vessels observe or hear a suspected UAV, crewmembers not needed for the safe navigation and operation of the vessel should be relocated to a safe space on the vessel until the threat has passed.
Limpet mines: Limpet mines have been used to damage commercial vessels on multiple occasions in recent years and are primarily a threat to commercial vessels in the Persian Gulf, Strait of Hormuz, and the Gulf of Oman. Limpet mines, or similar improvised explosive devices, can be attached to vessel hulls, above or below the waterline, via swimmers or small boats, while a vessel is berthed, at anchor, or underway.
When operating in these waters, U.S.-flagged commercial vessels should maintain a close lookout and remain vigilant for suspicious activity to include the approach of swimmers or small boats. Close attention should be given to the vessel’s waterline, especially at slow speeds, at anchor, and when moored.
If a mine has been, or was attempted to have been, attached to a vessel, crewmembers not needed for the safe navigation and operation of the vessel should be relocated to a safe space on the vessel until the threat has passed.
U.S.-flagged commercial vessels operating in these waters are advised to exercise caution, review security measures, and monitor VHF Channel 16.
