White House spokesman Scott McClellan on Wednesday said that for the Iraq Survey Group, which was leading the search for nuclear, biological and chemical weapons, "a lot of their mission is focused elsewhere now".
McClellan also said a report authored by the group's head, Charles Duelfer, which is to be released to the US Congress in the coming weeks, will be similar to a September draft in which he said there were no such weapons.
"Duelfer is continuing to wrap things up at this point... My understanding is that it is not going to fundamentally alter the findings of his earlier report," he said.
The White House confirmation came after The Washington Post reported the search for weapons of mass destruction in Iraq had ended before Christmas.
Duelfer's report to Congress said that deposed Iraqi leader Saddam Hussein had the intent but not the capacity to make weapons of mass destruction.
Hussein's alleged WMD stock was
the purported reason for invasion
The report contradicted the US government's chief publicly stated reason for invading Iraq.
McClellan recalled that US President George Bush decided in October, after Duelfer's first report, to revamp US intelligence operations.
"The president made it clear back in October that we need to make sure that we get the best possible intelligence," McClellan said. "We had a 12-year accumulated body of evidence we had, and our allies had, that was wrong, and we must correct the flaws."
Reacting to the news of the inspection's end, the Democratic leader in the House of Representatives blasted Bush's Iraq policy.
"President Bush has refused to concede what has been obvious for months - the primary justification for the invasion of Iraq was not supported by fact," House Minority Leader Nancy Pelosi said in a statement.
"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."