Iran's Islamic Revolutionary Guards Corps (IRGC) is accusing a U.S. Coast Guard vessel of "provocation" after Washington said the ship fired warning shots against approaching Iranian military boats in the Persian Gulf.
The IRGC said on May 11 its boats had encountered the U.S. ships the previous day, and accused them of "unprofessional behavior, such as flying helicopters, firing flares, and aimless and provocative shooting."
According to the Pentagon, the U.S. Coast Guard ship Maui fired about 30 warning shots after 13 fast boats from the IRGC's navy came close to it and other U.S. vessels in the Strait of Hormuz.
Spokesman John Kirby said the warning shots were fired after the fast boats came as close as 150 meters from six U.S. military vessels that were escorting the guided-missile submarine Georgia.
The Iranian boats had been acting "very aggressively," Kirby said.
It was the second time over the past month that U.S. military vessels had to fire warning shots because of what they said was unsafe behavior by Iranian vessels in the region, after a relative lull in such interactions over the past year.
The latest incident came as world powers and Iran seek to speed up efforts to bring Washington and Tehran back into compliance with the 2015 nuclear deal.
Four rounds of indirect talks between U.S. and Iranian officials in Vienna on reviving the agreement have yet to make major progress.