A U.S. Navy patrol coastal ship was harassed by seven Iranian vessels on Sunday and narrowly avoided colliding with one, in the latest in a string of incidents in the Persian Gulf.

Seven Islamic Revolutionary Guard Corps Navy (IRGCN) fast in-shore attack craft (FIAC) approached USS Firebolt (PC-10) while it was operating in international waters in the central Persian Gulf on Sept. 4, a defense official told USNI News.

Three of the FIACs maneuvered close to Firebolt, mirroring the ship's course and speed at a distance of about 500 yards for about eight minutes before leaving. Another FIAC then sped towards Firebolt and stopped directly in front of the ship, causing the Firebolt crew to maneuver to avoid a collision. The U.S. ship and Iranian FIAC came within 100 yards of one another, the defense official said.