The president could be seen bending over to peer at the floor of the Oval Office

At a black-tie dinner for journalists, Mr Bush narrated a slide show poking fun at himself and other members of his administration.

One pictured Mr Bush looking under a piece of furniture in the Oval Office, at which the president remarked: "Those weapons of mass destruction have got to be here somewhere."

After another one, showing him scouring the corner of a room, Mr Bush said: "No, no weapons over there," he said.

And as a third picture, this time showing him leaning over, appeared on the screen the president was heard to say: "Maybe under here?"

If George Bush thinks his deceptive rationale for going to war is a laughing matter, then he's even more out of touch than we thought

John Kerry

Democratic Party challenger for the presidency

The joke about the fruitless search for Iraqi WMDs so far, Washington's prime justification for the US-led invasion, has been branded as tasteless and ill-judged.

'Undermining' sacrifices

Mr Bush's election challenger Senator John Kerry described the president's attitude as "stunningly cavalier".

"If George Bush thinks his deceptive rationale for going to war is a laughing matter, then he's even more out of touch than we thought," he said in a written statement.

"Unfortunately for the president, this is not a joke."

Mr Kerry's statement also included a comment from Iraq war veteran Brad Owens, who said: "War is the single most serious event that a president or government can carry its people into.

"This cheapens the sacrifice that American soldiers and their families are dealing with every single day."

More than 500 US soldiers have died in the war and thousands more have been injured.

US Defence Secretary Donald Rumsfeld was asked what he thought of this incident at a press conference on Friday, but he dodged the issue, saying that he couldn't comment as he hadn't been at the event.