Bush told reporters the September 11 2001 attacks on New York and Washington changed US strategy on Iraq, necessitating action against the country because of the danger it posed.

"Nine-11 changed my calculation," he said.

"It made it really clear we have to deal with threats before they come on our shore.

"You know, for a long period of time we thought oceans could protect us from danger and we learned a tough lesson on September the 11th.

"It's really important for this nation to continue to chase down and deal with threats before they materialize and we learned that on September the 11th."

But Bush sidestepped questions on the post-war failure to find weapons of mass destruction (WMD) in Iraq on which Bush and British Prime Minister Tony Blair had based their decision to invade and topple the regime of Saddam Hussein.

However, the president had acknowledged last week that the US possessed no proof that Saddam was implicated in the September 11 attacks, while polls showed that nearly six out of every 10 polled in the United States believed otherwise.

White House spokesman Scott McClellan said earlier Thursday that the administration is still convinced that Iraq has chemical or biological weapons, despite a draft report by experts that makes no determination on the issue.

"We continue to believe that (Saddam) possessed weapons of mass destruction and weapons of mass destruction programs," McClellan told reporters here.

An interim US report on weapons of mass destruction in Iraq, due to be released in the coming weeks and the first of its kind since the end of the US-led war, draws no definitive conclusion on whether there are any such weapons in the country, the Central Intelligence Agency announced Wednesday.

McClellan stressed that the report was only an interim evaluation and not the final version expected in early October.

He added that David Kay, the CIA's representative overseeing the search for weapons in Iraq, is going to get a "complete and full picture" of these weapons programs.

"Doctor Kay is continuing to go through miles of documents relating to the former regime's weapons of mass destruction and weapons of mass destruction programs," McClellan said.

The Iraq Survey Group, a group of 1,400 US and British scientists and military and intelligence experts working on the report, is led by Kay, a former chief UN weapons inspector.

Until now, the nagging debate over the reasons given by Britain and the United States for attacking Iraq has not attained the magnitude in the US that it has in Britain, where Blair has been under constant fire in the press and in parliament, accused of having exaggerated the pre-war threat.

WAR.WIRE