Claims about Saddam's weapons of mass destruction were a primary justification for the war, but U.S. forces have yet to find any such weapons. The House and Senate intelligence panels are looking into prewar intelligence on Iraq and how it was used by the Bush administration.
Mr. Bush said in his address to Congress in January that the British government had learned that Saddam recently sought significant quantities of uranium in Africa.
The president's statement in the State of the Union was incorrect because it was based on forged documents from the African nation of Niger, White House spokesman Ari Fleischer said Monday.
"The president's statement was based on the predicate of the yellow cake" uranium "from Niger," Fleischer told reporters. "So given the fact that the report on the yellow cake did not turn out to be accurate, that is reflective of the president's broader statement."
Fleischer's remarks follow assertions by an envoy sent by the CIA to Africa to investigate allegations about Iraq's nuclear weapons program. The envoy, Joseph Wilson, said Sunday that the Bush administration manipulated his findings, possibly to strengthen the rationale for war.
Wilson, a former U.S. ambassador to the West African nation of Gabon, was dispatched in February 2002 to explore whether Iraq tried to buy uranium from Niger.
Writing in a New York Times op-ed piece, Wilson said it did not take him long "to conclude that it was highly doubtful that any such transaction had ever taken place."
In an interview on NBC, Wilson insisted his doubts about the purported Iraq-Niger connection reached the highest levels of government, including Vice President Dick Cheney's office.
In fact, he said, Cheney's office inquired about the purported Niger-Iraq link.
"The question was asked of the CIA by the office of the vice president. The office of the vice president, I am absolutely convinced, received a very specific response to the question it asked, and that response was based upon my trip out there," Wilson said.
Yet nearly a year after he had returned and briefed CIA officials, the assertion that Saddam was trying to obtain uranium from Africa was included in Mr. Bush's State of the Union address.
The International Atomic Energy Agency told the United Nations in March — after the State of the Union — that the information about the uranium procurement efforts was based on forged documents.
A British parliamentary committee concluded Monday that Prime Minister Tony Blair's government mishandled intelligence material on Iraqi weapons — and said key questions remain about the allegations of an attempted uranium deal with Nigeria.
The committee, however, cleared ministers of deliberately misleading lawmakers.
Blair said Tuesday he had made a valid case for military action.
"I refute any suggestion that we misled Parliament or the people," Blair told the House of Commons Liaison Committee, stressing he stands "totally" behind the case he made for war.
"I am quite sure we did the right thing in removing Saddam Hussein because not merely was he a threat…to the wider world but it was an appalling regime that the world is well rid of."
On Monday, the Foreign Affairs Committee said Blair "misrepresented" the status of a dossier published in January.
Blair had referred to it as "further intelligence," although he acknowledged later that it contained material from a graduate thesis published on the Internet.
The committee said that another dossier on Iraqi weapons, published in September, gave undue prominence to an uncorroborated claim that Iraq could deploy biological or chemical weapons within 45 minutes of an order being given. It also said the "jury is still out" on the accuracy of the information contained in the intelligence document.
"The jury is not out at all," Blair retorted Tuesday. "There is no doubt that Saddam was developing weapons of mass destruction."
Blair said Tuesday he had no doubts that evidence of weapons of mass destruction programs would be found in Iraq, but said his case would not be weakened if no weapons were found.
Defense Secretary Geoff Hoon that coalition forces needed at least another four months to search for banned arms in Iraq.
The weapons dispute is taking a toll on support for the war in Britain. The Times of London says a poll of 1,000 adults over the weekend find support for the war slipped from 64 percent in April to 47 percent now. Opposition rose from 24 percent in April to 45 percent now.
The poll also found Blair was deemed less trustworthy than rival political leaders.
The dispute is also affecting Australia's government, which will undergo a parliamentary inquiry on the matter next month.
The Australian Broadcasting Company reports Prime Minister John Howard, while continuing to express confidence in the prewar intelligence, is distancing himself from the data passed to him by the United States and Britain.
"I had discussions myself with senior figures in the intelligence community, very senior figures in both countries," Howard said. "I believe that they believed very strongly in their judgments…We had lots of material put to us over a period of months and it built a case, necessarily judgments had to be made by the agencies."