The Central Intelligence Agency (CIA) has released the declassified summary of a report that accuses CIA officers of not having worked "effectively and cooperatively" against Al- Qaeda targets before 9/11.
A review by the CIA Office of Inspector General (OIG) found that CIA officers worked hard against Al- Qaeda targets but they "did not always work effectively and cooperatively", said the executive summary of OIG's report on CIA's performance prior to the September 11 attacks.
The report, released on Tuesday, said the OIG's review team had found neither a "single point of failure" nor a "silver bullet" that would have enabled the intelligence community to predict or prevent the 9/11 attacks.
But it said it found failure to implement and manage important processes, to follow through with orations and to properly share and analyse critical data.
If intelligence officers had been able to view and analyse the full range of information available before Sep 11, they could have developed a more informed context in which to assess the threat reporting of the spring and summer that year, the report said.
The US government and the intelligence agency, however, had not had a comprehensive strategy for combating Al-Qaeda before September 11, the report said.
The summary report, completed in June 2005, was declassified at the request of Congress, which passed a bill earlier this month to implement some of the recommendations of the 9/11 commission and asked the CIA's OIG to make available to the public within 30 days a version of the report's executive summary.
In a statement, CIA Director Mike Hayden said that while the agency was meeting "the dictates of the law, I want to make it clear that this declassification was neither my choice nor my preference".
He added that two directors of National Intelligence had supported the agency's position against the release of the report.
Hayden said the release of this report "would distract officers serving their country on the frontlines of a global conflict.
"It will, at a minimum, consume time and attention revisiting ground that is already well ploughed. I also remain deeply concerned about the chilling effect that may follow publication of the previously classified work, findings, and recommendations of the OIG," he said.
When the CIA was declassifying the report, it focused chiefly on the protection of essential sources and methods and it was unnecessary and unwise to permit identification of officers below the level of Centre Chief, even if only by title, and those passages had been deleted, Hayden said.
"Counter-terrorism is an exceptionally difficult challenge. The risks, and the stakes, are extremely high," he said.
Arguing that enemies of the US were "adaptive, resilient, and determined to strike us again here at home", Hayden acknowledged that there are limits to what intelligence can accomplish and that there can be no guarantee of perfect security.