Iran must bear the consequences of any new confrontation between US and Iranian vessels in the Strait of Hormuz, a senior US official warned yesterday.

Washington says Iranian boats aggressively approached three US Naval ships in the waterway, a major oil shipping route off Iran's coast, and threatened that the ships would explode.

"This was a very provocative act by the Iranians and ... came very close to resulting in an altercation between our forces and their forces," said Stephen Hadley, President George W. Bush's national security adviser.

"They've got to be very careful about this because if it happens again they are going to bear the consequences," Hadley told reporters travelling with Bush.

The United States released a video of the weekend incident, including a recording of what it said was the exchange between the two sides. Iran rejected the footage as fake and accused Washington of trying to stir up tension in the region. Iran's Revolutionary Guards said the images were archive pictures.