The US warned Iran yesterday against provocative military gestures that could flare out of control as it revealed how five Iranian Revolutionary Guard boats threatened to blow up three US warships at the weekend.

The confrontation happened on Sunday in the Strait of Hormuz, between Iran and the Gulf states, one of the world's most important waterways, the Pentagon said yesterday. It denounced Iran's behaviour as a "careless, reckless, dangerous and potential hostile act that clearly requires an explanation".