Iran has described the incident as an "ordinary occurrence"

Iranian footage

There is no sign of threatening behaviour by the Iranian boats, as alleged by US officials who said their actions were dangerous and provocative.

However, the four-minute clip does not appear to show the whole incident in the Strait of Hormuz on Sunday.

Iran accuses the US of faking video and audio evidence to support its claims.

"Coalition warship number 73 this is an Iranian patrol," the Iranian commander is heard to say in clear English in the footage, broadcast on Iran's English-language Press TV .

"This is coalition warship number 73. I am operating in international waters," comes the reply.

On Tuesday the US military released video and audio it said confirmed its allegation that Iranian speedboats harassed US warships and threatened to blow them up in a radio communication.

Iran described the incident as a routine contact which happens all the time in the crowded waters of the Gulf.

The confrontation has further inflamed tensions between arch-foes Iran and the United States.

US President George W Bush is currently on a tour of the Middle East which will tackle what the Americans see as the threat posed by Iran to regional stability.