The US Senate Intelligence Committee has severely criticised US spy agencies for overstating the threat of Iraqi weapons and ignoring contrary evidence.
The report also said US intelligence ignored doubts over Iraqi mobile bioweapons labs - one of the key elements cited by the Bush administration in making its case for the war against Iraq.
But the document, entitled Report on the US Intelligence Community's Assessment of Prewar Intelligence on Iraq, absolved the administration of charges it pressured analysts to fit its own war policy.
The main US justification for going to war against Iraq was that Baghdad posed a threat due to stockpiles of chemical and biological weapons and was attempting to develop nuclear weapons. No large stockpiles of banned weapons have been found since the US invasion last year.
The Senate Intelligence Committee had been working until the last moment with the CIA to get as much information as possible declassified for inclusion in the long-awaited report.