CIA report details 'brutal' post-9/11 interrogations
The CIA carried out "brutal" interrogations of al-Qaeda suspects in the years after the 9/11 attacks on the US, a US Senate report has said.
The summary of the report, compiled by Democrats on the Senate Intelligence Committee, said that the CIA misled Americans about what it was doing.
The information the CIA collected this way failed to secure information that foiled any threats, the report said.
In a statement, the CIA insisted that the interrogations did help save lives.
"The intelligence gained from the programme was critical to our understanding of al-Qaeda and continues to inform our counterterrorism efforts to this day," Director John Brennan said in a statement.
However, the CIA said it acknowledged that there were mistakes in the programme, especially early on when it was unprepared for the scale of the operation to detain and interrogate prisoners.
The programme - known internally as the Rendition, Detention and Interrogation programme - took place from 2002-07, during the presidency of George W Bush.
Suspects were interrogated using methods such as waterboarding, slapping, humiliation, exposure to cold and sleep deprivation.
Analysis: Frank Gardner, BBC security correspondent
This report makes deeply uncomfortable reading but it shines a much-needed torch into some dark places.
The fact that "Enhanced Interrogation Techniques" (EIT), or torture by any other name, was stopped years ago or that some people at the top of the US administration may not have known its full extent, does not excuse the fact it took place at all.
After going through six million pages of documents, the authors concluded that in none of the cases they looked at did these brutal methods stop a terrorist attack. Meaning that America's reputation, and by extension that of the wider West, has been sullied for no tangible gain.
This will lay the US open to charges of hypocrisy, making it far harder for the West to criticise brutal and dictatorial regimes. It may also encourage terrorists to justify their atrocities by pointing to this past abuse.
It can only be hoped this report's publication means these practices will be consigned to history's dustbin.
Introducing the report to the Senate, Intelligence Committee Chairwoman Dianne Feinstein described the CIA's actions as a stain on US history.
"The release of this 500-page summary cannot remove that stain, but it can and does say to our people and the world that America is big enough to admit when it's wrong and confident enough to learn from its mistakes," she said.
"Under any common meaning of the term, CIA detainees were tortured," she added.
Earlier, President Obama responded to the report, saying the methods used were inconsistent with US values.
"These techniques did significant damage to America's standing in the world and made it harder to pursue our interests with allies and partners," he said in a statement.
Reacting to the release of the report summary, the Senate Republican leaders insisted that the methods used helped in the capture of important suspects and the killing of Osama bin Laden.
"Claims included in this report that assert the contrary are simply wrong," Senators Mitch McConnell and Saxby Chambliss said in a joint statement.
The Senate committee's report runs to more than 6,000 pages, drawing on huge quantities of evidence, but it remains classified and only a 480-page summary has been released.
Its main points include the following:
- At no time did coercive interrogation techniques lead of collection of intelligence on imminent threats
- None of 20 cases of counterterrorism "successes" attributed to the techniques led to unique or otherwise unavailable intelligence
- The CIA misled politicians and public, giving inaccurate information to obtain approval for using techniques
- The CIA claimed falsely that no senators had objected to the programme.
- Management of the programme was deeply flawed, for example the operation of the second detention facility, known as COBALT
- At least 26 of 119 known detainees in custody during the life of the programme were wrongfully held, and many held for months longer than they should have been
- Aggressive techniques were used on suspects from the start, despite CIA claims that interrogations would begin with less coercive methods
- Methods included sleep deprivation for up to 180 hours, often standing or in painful positions
- Waterboarding was physically harmful to prisoners, causing convulsions and vomiting
Mr Obama halted the CIA interrogation programme when he took office in 2009.
Earlier this year, he said that in his view the methods used to question al-Qaeda prisoners amounted to torture.
Publication of the report had been delayed amid disagreements in Washington over what should be made public.
Security was increased at US facilities around the world ahead of publication.
Embassies and other sites were taking precautions amid "some indications" of "greater risk", a White House spokesman said.
US Defence Secretary Chuck Hagel said he had ordered all top US military commanders to be on high alert.
17 September 2001: President Bush authorises CIA to detain suspected terrorists
August 2002: Abu Zubaydah, a Saudi terror suspect, subjected to persistent "coercive interrogation", including waterboarding
November 2002: Abd al-Rahim al-Nashiri transferred to CIA custody and subjected to waterboarding.
March 2003: Khalid Sheikh Mohammed, suspected 9/11 mastermind, captured - later waterboarded 183 times
2 November 2005: Washington Post reveals existence of global CIA interrogation programme
8-9 November 2005: CIA authorises destruction of "coercive interrogation" videotapes
September 2006: President Bush publicly acknowledges the programme for the first time
March 2008: President Bush vetoes legislation to limit CIA interrogation techniques.
January 2009: President Barack Obama bans the CIA's detention authority and limits interrogation to techniques authorised by the Army Field Manual.
US intelligence agencies were accused of using "extraordinary rendition" to send terror suspects for questioning in countries where they had no legal protection or rights under American law. Some of the suspects claimed they had been tortured in countries such as Syria and Egypt.
A Council of Europe report in 2006 said it had pieced together details of a "spider's web of secret detentions and unlawful inter-state transfers", based on evidence from detainees' testimonies, flight plans and other publicly-available information.
The Senate report released on Tuesday said that the CIA sent some of its al-Qaeda suspects to detention centres in other countries, but did not say which ones.