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.