UPDATED 7.30am: The CIA's interrogation of al-Qaeda suspects was far more brutal than acknowledged and did not produce useful intelligence, a damning and long-delayed US Senate report says.

The Central Intelligence Agency also misled the White House and Congress with inaccurate claims about the program's usefulness in thwarting attacks, the Senate Intelligence Committee said on Tuesday.

As the 500-page declassified summary of the committee's report was released, President Barack Obama admitted that the CIA's actions had been counterproductive and "contrary to our values".

Current CIA director John Brennan defended his agency's adoption of tough tactics under president George W Bush in the aftermath of the September 11, 2001 al-Qaeda attacks on US cities.

He insisted that, while mistakes were made, brutal techniques like waterboarding "did produce intelligence that helped thwart attack plans, capture terrorists and save lives".
US embassies were on alert as committee chair Senator Dianne Feinstein pushed ahead with publication, despite Secretary of State John Kerry warning that it could provoke anger around the world.

The summary is the most extensive detailing of the CIA's brutal interrogation of al-Qaeda suspects yet.

Feinstein told the Senate that at least 119 individuals were subjected to "coercive interrogation techniques, in some cases amounting to torture".

The detainees were rounded up by US operatives beginning in 2001 after al-Qaeda destroyed the World Trade Centre in New York and damaged the Pentagon, and through to 2009.

They were interrogated either at CIA-run secret prisons in allied nations or at the US detention centre at Guantanamo Bay, Cuba.

Feinstein said some around the world "will try to use it to justify evil actions or incite more violence".

"We can't prevent that. But history will judge us by our commitment to a just society governed by law, and the willingness to face an ugly truth and say 'never again'."
While heavily redacted, the report is damning.

"The interrogations of CIA detainees were brutal and far worse than the CIA represented to policymakers and others," it said.

The report - a review of more than six million pages of documents - concluded "the use of the CIA's enhanced interrogation techniques was not an effective means of obtaining accurate information or gaining detainee cooperation".

Seven of the 39 detainees known to have been subjected to the enhanced interrogations "produced no intelligence while in CIA custody.

The report noted that in many cases "there was no relationship" between cited counter-terrorism successes and information obtained during the enhanced interrogation.

"In the remaining cases, the CIA inaccurately claimed that specific, otherwise unavailable information was acquired from a CIA detainee 'as a result' of the CIA's enhanced interrogation techniques."

Rights advocates have hailed the exposure of the secret program.

Human Rights Watch national security counsel Laura Pitter said: "We hope the release of the summary will be the beginning, not the end, of investigations into US torture to ensure it never happens again"