Under strong political pressure, President George Bush established a bipartisan commission on Friday to investigate the failures.
Claims that Iraq had stockpiles of weapons of mass destruction were the main reason cited by Bush for the Iraq war, in which more than 500 US troops have died. According to the independent website, iraqbodycount.net, Iraqi civilian casualties could be as high as 10,000.
Bush noted during a press conference that former chief US weapons hunter David Kay had failed to confirm prewar intelligence that Iraq possessed weapons of mass destruction.
"We are determined to figure out why," he said. "We're also determined to make sure that American intelligence is as accurate as possible for every challenge in the future."
However, opposition Democrats immediately questioned the independence of the commission since its members were handpicked by Bush.
They want the panel to investigate whether the Bush administration hyped up the threat.
"To have a commission appointed exclusively by President Bush investigate his administration's intelligence failures in Iraq does not inspire confidence in its independence," said Nancy Pelosi of California, leader of the Democratic minority in the House of Representatives.
"To have a commission appointed exclusively by President Bush investigate his administration's intelligence failures in Iraq does not inspire confidence in its independence"
US Democrat leader
And Henry Waxman, a California Democrat, said the commission "may provide President Bush with political cover, but it won't result in the investigation that the nation needs".
The commission will have nine members, seven of whom were named on Friday.
- Chuck Robb, 64, is a former Democratic senator. A Marine Corps reserve member from 1970-1991, he fought in Vietnam.
Robb was governor of Virginia from 1982-1986, and was elected to the US Senate where he served from 1988-2000. He was on the Armed Forces and Intelligence committees.
- Laurence Silberman, 68, is a judge and a Republican. He was named to the federal appeals court for Washington by Ronald Reagan in 1985, a politically sensitive post in which he overturned the conviction of Oliver North in the Irangate scandal.
He also served as US ambassador to Yugoslavia 1975-77, and has been a law professor at several prestigious US universities.
- John McCain, 67, has been a Republican senator from Arizona since 1982. A former pilot and prisoner in Vietnam, in 2000 he sought the Republican presidential nomination.
A member of the Senate Armed Forces committee, McCain has already said he does not think Bush exaggerated the evidence to bolster his case for war.
- Lloyd Cutler, 87, is a Democrat, legal scholar and consummate Washington insider.
He was a legal adviser to the White House during the presidencies of Jimmy Carter and Bill Clinton.
Rick Levin, 56, is a Democrat and has been president of Bush's alma mater, Yale University, since 1993. He is an economist by training.
McCain (C) has said he does not
believe Bush hyped Iraq's threat
- Bill Studeman, 64, is an admiral and former deputy director of the CIA (1992-1995) - a post to which he was named by George Bush senior.
A naval intelligence officer, he served four tours of duty in Vietnam. He was also director of naval intelligence (1985-1988), before leading the National Security Agency.
- Pat Wald, 75, has been a judge at the Hague-based International Criminal Court since 1992.
She was named to the Washington federal appeals court in 1977 by then-president Jimmy Carter, a Democrat.
But Wald retired in 1999 and became an ICC magistrate whose work has included trials of the first criminals from the former Yugoslavia.