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 on his first official visit to Israel.

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.

“America aims to implement this plan saying Iran has been and is the source of fear in the Middle East,” Defence Minister Mostafa Mohammad Najjar was quoted by state television as saying. “Iranian craft always ask other ships to identify themselves and this is what they did to the American ships. American ships answered and that was it.”

Bush called the incident provocative before leaving Washington on a Middle East trip aimed at nurturing Israeli-Palestinian peace efforts and rallying Arab opposition to Iran and its growing regional influence.

The encounter was the latest sign of tension between Washington and Tehran, at odds over Iran's nuclear programme and who is to blame for the violence in Iraq.

"...It's the kind of incident that can provoke exchange of fire and we think the Iranians need to be on notice that they are fishing in Iran's Revolutionary Guards rejected the video released by the US Department of Defense as a fake, Iranian television reported, saying the images were archive pictures.