U.S. 5th Fleet spotted IRGCN support ship Shahid Baziar towing the USV around 11 p.m. local time Monday, according to the release. Navy patrol coastal ship USS Thunderbolt (PC-12), which was operating nearby, responded while 5th Fleet also sent a MH-60S Sea Hawk from the Helicopter Sea Combat Squadron 26 out of Bahrain.

Shahid Baziar detached its towing line from the USV and left the waters about four hours after the U.S. responded.

“IRGCN’s actions were flagrant, unwarranted and inconsistent with the behavior of a professional maritime force,” Vice Adm. Brad Cooper, the commander of U.S. Naval Forces Central Command, U.S. 5th Fleet and Combined Maritime Forces, said in the release. “U.S. naval forces remain vigilant and will continue to fly, sail and operate anywhere international law allows while promoting rules-based international order throughout the region.” 

This is the second time this summer that IRGCN has had unsafe interactions with the U.S. Navy vessels in the Persian Gulf. In June, three Iranian fast attack craft harassed two Navy ships, USNI News previously reported.

The ships sailed at Cyclone-class patrol coastal ship USS Sirocco (PC-6) and Spearhead-class USNS Choctaw County (T-EPF-2), coming within 50 yards, according to a 5th Fleet statement. The Iranian fast attack crafts approached Sirocco at high speeds and changed course when Sirocco’s crew sent audible warnings.

Naval Forces Central Command launched the Saildrone Explorer in the Persian Gulf on Jan. 27, following a month-long test period in the Gulf of Aqaba, according to a Central Command press release. The USV is part of Task Force 59, headquartered in Bahrain, which stood up nearly a year ago to test unmanned and contractor-owned vessels in the Middle East.

The goal of the task force is to have 100 unmanned platforms, belonging to the U.S. and allies, operating together by the end of 2023, USNI News previously reported.