A CIA inquiry has accused the agency's ex-chief George Tenet and his aides of failing to prepare for al-Qaeda threats before the 9/11 attacks on the US.
George Tenet flatly rejected the charges levelled at him
"The agency and its officers did not discharge their responsibilities in a satisfactory manner," the CIA inspector general wrote in a scathing report.
The document was completed in June 2005 and kept classified until now. Its release was ordered by Congress.
Mr Tenet, former CIA director, said the inspector general was "flat wrong".
But some former CIA employees have told the BBC that the criticisms are justified.
Mr Tenet, who enjoyed strong support from President George W Bush, resigned in 2004 citing "personal reasons".
The review team led by Inspector General John Helgerson found no "single point of failure" that would have stopped the attacks on 11 September 2001.
But he says US spy agencies lacked a comprehensive plan to counter al-Qaeda.
The report concludes that Mr Tenet, "by virtue of his position, bears ultimate responsibility for the fact that no such strategic plan was ever created".
It adds that various bodies "did not always work effectively and cooperatively".
For the record
Mr Helgerson called for accountability boards to look at the performance of Mr Tenet and his aides.
Such a move was rejected after the internal report was submitted to CIA leaders.
Current CIA Director Michael Hayden said the decision to release the report was not his preference, but that he was making it available as required by Congress in a law signed by Mr Bush earlier this month.
"I thought the release of this report would distract officers serving their country on the front lines of a global conflict," he said.
The BBC's James Coomarasamy says the criticism is in keeping with previous inquiries into the 11 September attacks.
It is notable, however, for having an unusually critical tone for an internal inquiry and for its personal criticism of Mr Tenet.
In a statement, the former CIA director said he had implemented a "robust plan, marked by extraordinary effort and dedication to fighting terrorism, dating back to long before 9/11".
"Without such an effort," Mr Tenet added, "we would not have been able to give the president a plan on September 15, 2001, that led to the routing of the Taleban... and combating terrorists across 92 countries".
But former CIA analyst Ray McGovern told the BBC the inspector general's criticism was justified.
"... [George Tenet] was too busy schmoozing with foreign leaders and getting sort of swamped with the detail that he forgot that his job was to manage the intelligence community and so the cracks such as existed became wider and wider. He didn't talk to the FBI and 9/11 happened."
Meanwhile, the former head of the CIA's Osama bin Laden unit, Michael Scheuer, described the agency's rank-and-file employees under Mr Tenet as "lions led by asses".
"Many of the difficulties that were listed in that report today - the inability to share information, the lack of people to support and run operations against Osama bin Laden - those were problems that were brought to Mr Tenet's attention as early as 1996 and he never did anything about them," he told the BBC.
Our correspondent says the administration has already taken steps to address some criticisms against the intelligence community, making this latest report more of an interesting historical document than a consequential one.
But Lori Van Auken - whose husband, Kenneth, died in the World Trade Center attack - said of the report: "We're talking about complete and utter incompetence, and people should be held accountable and we should know who they are..."