President Donald Trump has said the US Navy destroyed an Iranian drone in the Strait of Hormuz.
He said the USS Boxer amphibious assault ship "took defensive action" on Thursday after the drone came within about 1,000 yards (914m) of the vessel.
Iran said it had no information about losing a drone. In June, Iran downed a US military drone in the area.
Iran has been blamed by the US for attacks on tankers since May in the world's key shipping area. Tehran denies all the accusations.
The recent incidents have triggered fears of a military conflict in the region.