"We are aware of the Iranian exercise involving attacking a mock-up of a vessel similar to a motionless aircraft carrier," US Fifth Fleet spokeswoman Rebecca Rebarich told AFP.

"While we are always watchful of this type of irresponsible and reckless behaviour by Iran in the vicinity of busy international waterways, this exercise has not disrupted coalition operations in the area nor had any impacts to the free flow of commerce in the Strait of Hormuz and surrounding waters."