US Navy reports harassment by Iranian boats in Strait of Hormuz

Two Iranian Islamic Revolutionary Guard Corps Navy (IRGCN) fast in-shore attack craft (FIAC), a type of speedboat armed with machine guns, conducted unsafe and unprofessional manoeuvres while operating in close proximity to US naval vessels transiting the Strait of Hormuz, May 10, 2021. (Photo: US Navy)

The US Navy has disclosed that Iranian Islamic Revolutionary Guard Corps Navy (IRGCN) fast in-shore attack craft (FIAC) armed with machine guns conducted unsafe and unprofessional manoeuvres and failed to exercise due regard for the safety of US forces as required under international law while operating in close proximity to US naval vessels transiting the Strait of Hormuz.

A group of 13 IRGCN FIACs made a high-speed approach on the guided-missile cruiser USS Monterey, the patrol coastal ships USS Thunderbolt, USS Hurricane, and USS Squall, the US Coast Guard patrol boats Wrangell and Maui, and the guided-missile submarine USS Georgia on Monday, May 10.

The navy said the US vessels were exercising transit passage in the Strait of Hormuz in accordance with customary international law. The US surface vessels were escorting Georgia, as the submarine was transiting on the surface.

Two of the IRGCN vessels broke away from the larger group, transited to the opposite side of the US formation, and approached Maui and Squall from behind at a high rate of speed (in excess of 32 knots) with their weapons uncovered and manned. The remaining 11 FIACs maintained position, which placed the formation of the US ships in between the two IRGCN groups.

In order to de-escalate the situation and ensure the safety of all ships and personnel, the US crews issued multiple warning to both groups of IRCGN vessels. Maui and Squall‘s warning to the group of two included repeated bridge-to-bridge verbal warnings, five acoustic device warnings, and five short blasts of the ships’ horns, the internationally recognised danger signal outlined in the International Regulations for Preventing Collisions at Sea (COLREGs).

After the two IRGCN vessels failed to respond to repeated warnings and closed within 300 yards (274 metres), Maui exercised lawful de-escalatory measures by firing warning shots. The two IRGCN vessels again failed to respond to warnings and closed to within 150 yards (137 metres) of Maui, at which time the coast guard boat fired additional warning shots.

After the US naval ships’ repeated verbal and acoustic warnings, sounded five blasts of the ship’s horn, and fired warning shots, the two FIACs altered course and increased their distance from the US forces.

During the interaction, the IRGCN vessels came within 150 yards of Maui, which the navy said was an unnecessarily close range that put the US ships and their crews in immediate danger.

The navy said the two IRGCN vessels’ actions when coupled with the actions of the larger group of FIACs increased the risk of miscalculation and collision and were not in accordance with the internationally recognised COLREGS’ “rules of the road” or internationally recognised maritime customs.

This latest encounter between US and Iranian naval vessels comes less than a month following an earlier incident wherein US and Iranian vessels nearly collided with each other in the northern Arabian Gulf.

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