The search for weapons of mass destruction (search) in Iraq has quietly concluded without any evidence of the banned weapons that President Bush cited as justification for going to war, the White House said Wednesday.

Democrats said Bush owes the country an explanation of why he was so wrong.

The Iraq Survey Group (search), made up of some 1,200 military and intelligence specialists and support staff, spent nearly two years searching military installations, factories and laboratories whose equipment and products might be converted quickly to making weapons.

• Click here to read the Duelfer report's key findings (pdf).

• Click here to read Vol. 1 of the report (pdf).

• Click here to read Vol. 2 (pdf).

• Click here to read Vol. 3 (pdf).

White House press secretary Scott McClellan said there no longer is an active search for weapons and the administration does not hold out hopes that any weapons will be found. "There may be a couple, a few people, that are focused on that" but that it has largely concluded, he said.

"If they have any reports of [weapons of mass destruction] obviously they'll continue to follow up on those reports," McClellan said. "A lot of their mission is focused elsewhere now."

House Democratic Leader Nancy Pelosi of California said Bush should explain what happened.

"Now that the search is finished, President Bush needs to explain to the American people why he was so wrong, for so long, about the reasons for war," she said.

"After a war that has consumed nearly two years and millions of dollars, and a war that has cost thousands of lives, no weapons of mass destruction have been found, nor has any evidence been uncovered that such weapons were moved to another country," Pelosi said in a written statement. "Not only was there not an imminent threat to the United States, the threat described in such alarmist tones by President Bush and the most senior members of his administration did not exist at all."

Chief U.S. weapons hunter Charles Duelfer (search) is to deliver his final report on the search next month. "It's not going to fundamentally alter the findings of his earlier report," McClellan said, referring to preliminary findings from last September. Duelfer reported then that Saddam Hussein not only had no weapons of mass destruction and had not made any since 1991, but that he had no capability of making any either. Bush unapologetically defended his decision to invade Iraq.

"Nothing's changed in terms of his views when it comes to Iraq, what he has previously stated and what you have previously heard," McClellan said. "The president knows that by advancing freedom in a dangerous region we are making the world a safer place."

Bush has appointed a panel to investigate why the intelligence about Iraq's weapons was wrong.

McClellan said the Iraq experience would not make Bush hesitant to raise alarms when he deems it necessary.

"But we're also going to continue taking steps to make sure that that intelligence is the best possible," he said.

"Our friends and allies had the same intelligence that we had when it came to Saddam Hussein," McClellan said. "And now we need to continue to move forward to find out what went wrong and to correct those flaws."

At the State Department, spokesman Richard Boucher said Wednesday about 120 Iraqi scientists who had been working in weapons programs were being paid by the U.S. government to work in other fields.