A U.S. military ship fired warning shots after three vessels from Iran's Islamic Revolutionary Guard Corps Navy (IRGCN) came close to it and another American patrol boat in the Gulf, the United States military said on Tuesday.
Such incidents have occurred occasionally over the past five years, though there has been a relative lull over the past year.
"The U.S. crews issued multiple warnings via bridge-to-bridge radio and loud-hailer devices, but the IRGCN vessels continued their close range maneuvers," the military statement said.
"The crew of Firebolt then fired warning shots, and the IRGCN vessels moved away to a safe distance from the U.S. vessels," the statement added, using the name for the U.S. Navy patrol ship.
The closest the Iranian fast inshore attack craft came to the American ships was 68 yards (204 feet) during the incident, which took place on Monday in international water in the northern Gulf.