Persistent threats to merchant vessels in the Red Sea, Gulf of Aden and Persian Gulf and its approaches

Updated 18 December 2023

Regional conflicts, heightened military activity, and increased political tensions continue to pose threats to commercial vessels operating in in these regions, warns flag administrations. And with the escalation of the Israel-Gaza conflict, tensions in the Southern Red Sea region have escalated even further, particularly for assets with a link to Israel. See our alert Red Sea - situation update for additional advice.

The Republic of the Marshall Islands (RMI) Maritime Administrator on 14 December 2023 updated its ship security advisory SSA-03-23, warning vessels transiting the Arabian/Persian Gulf, Arabian Sea, Bab-al-Mandeb, Gulf of Aden, Gulf of Oman, Strait of Hormuz, and Red Sea about the increased military activity and level of political tension in these regions and advises them to maintain a heightened level of vigilance.

A similar warning went out to vessels earlier this year from the US Maritime Administration (MARAD) and on 6 September 2023, MARAD renewed its advisory (2023-011) to US flagged commercial vessels operating in the same regions. Since then, MARAD has also published a maritime alert on the current situation in the Southern Red Sea.

These warnings came in reaction to the many instances of commercial vessels reportedly being harassed and/or seized by foreign military vessels when transiting the Persian Gulf and its approaches. According to the two flag administrations, local military forces in this area have used small boats and/or helicopters to board commercial vessels and attempted to force these vessels into their territorial waters. Although some past incidents may have targeted specific commercial vessels due to their association with certain countries, cargoes, individuals, or companies, not all did. The possibility for miscalculation or misidentification therefore remains, potentially leading to aggressive actions against any commercial vessel, say the two administrations.

MARAD further emphasises that, in addition to illegal boardings and seizures, threats in the wider Gulf of Aden and Red Sea regions may come from a number of different sources including, but not limited to, drones (unmanned aerial vehicles (UAVs)), limpet mines, explosive boats, and pirates and armed robbers. With little or no warning, vessels operating in these areas may also encounter navigation or communication disruptions, such as GPS interference, AIS spoofing, and bridge-to-bridge communication spoofing. 


Risk mitigation measures

Vessels operating in the waters listed above are advised to exercise caution, review security measures, ensure that AIS is always transmitting (except in extraordinary circumstances) in accordance with the provisions of the International Convention for Safety of Life at Sea (SOLAS), and monitor VHF Channel 16. In addition, vessels are recommended to take the following precautions when operating in the region:

  • Undertake a pre-voyage threat and risk assessment before entering any region where there has been an incident or where the threat has changed.
  • Review the Ship Security Plan and amend it, if necessary, after performing the pre-voyage threat and risk assessment. Take advice from industry-issued best practices.
  • Conduct security training and drills prior to entering areas of increased risk.
  • Strictly observe any exclusion zones or guidance issued by coastal states.
  • Maintain a full and vigilant bridge watch for any small craft approaching. However, masters are reminded that fishermen in the region may try to protect their nets by attempting to aggressively approach merchant vessels and that some of them may be armed to protect their catch.
  • Participate in all available applicable voluntary reporting schemes to ensure communication is maintained directly with coalition forces in the regions (UKMTO, IMSC and EMASoH, as applicable). Immediately report any incident or suspicious activity.
  • Answer all VHF calls professionally. Do not ignore!

The Maritime Global Security website at offers industry-issued best practices, including guidance to mariners by geographic region, such as the BMP5 and the Interim Industry Transit Advice for the Southern Red Sea and Gulf of Aden, and provides contact and subscription information for regional maritime security reporting centers. The Maritime Global Security website should be consulted prior to operating in the above listed areas.

Removal of the Indian Ocean High Risk Area

Vessel operators and masters are likely aware of the industry’s decision to remove the Indian Ocean High Risk Area (HRA) for piracy as of 1 January 2023. However, threat and risk assessments should still be conducted also after this date, and best management practices followed to continue to mitigate the risks presented by any remaining security threats in the region. Furthermore, the Voluntary Reporting Area (VRA) administered by the United Kingdom Maritime Trade Operations (UKMTO) has not changed. Vessels entering the VRA are encouraged to continue to report to the UKMTO and register with the Maritime Security Centre for the Horn of Africa (MSCHOA) in accordance with the BMP5.

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