WASHINGTON: 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 said Tuesday.

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.

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 the 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, although Obama admitted in August that: “We tortured some folks."

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 Center 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 center 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,” while others “provided significant accurate intelligence prior to, or without having been subjected to these techniques."

The report noted that in many cases “there was no relationship” between cited counterterrorism 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.

“Since coming to office in 2009, Obama has sought to distance the United States from past deeds and outlawed harsh interrogation.

Declassified

In April, Feinstein's committee voted overwhelmingly to release the severely critical executive summary and 20 conclusions of the secret document.

But first the lawmakers had to negotiate with the White House on redactions, something Feinstein pledged to do.

The undertaking caused deep friction between the intelligence community and the lawmakers and Senate staffers.

“We've declassified as much of that report as we can,” White House spokesman Josh Earnest said Monday.

“The president believes that on principle it's important to release that report so that people around the world and people here at home understand exactly what transpired."

The State Department has put its missions around the world on watch, and asked them to review security arrangements ahead of the report's release.

Democratic Senator Claire McCaskill supports the report's release, calling it “a gut check moment for our democracy.

“Former Bush vice president Dick Cheney staunchly defended the interrogation program, telling The New York Times it was “absolutely, totally justified."

“When we had that program in place, we kept the country safe from any more mass casualty attacks, which was our objective,” he said.

But rights advocates 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."