US spymaster John Brennan admitted Thursday that some CIA interrogators had used unauthorized and "abhorrent" tactics in the past decade and said he believes torture tends to lead to false intelligence.
In an extraordinary news conference, broadcast live from the agency's Langley headquarters in what is believed to be a first in CIA history, Brennan mounted a stout defense of his officers, saying the vast majority of them did not mistreat prisoners.
But, in the wake of a damning Senate report into CIA treatment of Al-Qaeda suspects that triggered global revulsion, he confirmed that some had gone beyond their orders and abused detainees.
Brennan said the torture came amid fear of another wave of violence from Al-Qaeda after the September 11, 2001 attacks, as the Central Intelligence Agency scrambled to take on a task it had virtually no experience with.
"We were not prepared," he said, describing how then president George W. Bush had approved the so-called "enhanced interrogation techniques" now denounced as torture.
President Barack Obama halted the program upon taking office in 2009 and has since described the Bush-era use of torture by the CIA as counterproductive and an affront to American values.
"In a limited number of cases, agency officers used interrogation techniques that had not been authorized, were abhorrent and rightly should be repudiated by all," Brennan said.
Amid a political row about whether Bush was right to order tough tactics in the wake of the attacks, Brennan said it is impossible to know whether harsh interrogations had won useful intelligence.
"I tend to believe that the use of coercive methods has a strong prospect for resulting in false information," he said.
- Avoiding the word 'torture' -
Brennan said information from detainees was indeed useful in the hunt for Osama bin Laden, but it was impossible to say whether the "enhanced" interrogation had been necessary.
"There's no way to know if information obtained from an individual who had been subjected at some point during his confinement could have been obtained through other means," he said.
Brennan refused to say whether the methods amounted to torture, but said the CIA was no longer involved in detaining and interrogating suspects and has adopted reforms to prevent such abuses from happening again.
As the program had been scrapped, it was time to "move forward," he said.
But Brennan blasted this week's Senate intelligence committee report that accused the CIA of misleading the US government and public for years about the scale and success of its torture methods.
Committee chair Senator Dianne Feinstein, who released the report after a long wrangle with the CIA over what should be redacted, responded to Brennan point-by-point during his appearance.
"CIA helps keep our nation safe, strong. Torture does not. We must learn from our mistakes," her staff wrote on Twitter.
She said the 500-page executive summary released on Tuesday was a small part of a 6,700-page report, and denied that lawmakers had cherry-picked damning material.
And she disputed the idea that it could not be known whether torture -- known as enhanced interrogation techniques, or EITs -- had led the CIA to its quarry.
"Study definitively proves EITs did not lead to bin Laden. Page 378," her staff tweeted.
The report into the spy agency's abuse of Al-Qaeda suspects in a network of secret prisons around the world between 2002 and 2009 triggered global outrage and demands for justice.
Rights groups demanded US prosecutors charge officials who approved the torture.
"If we don't hold officials accountable for ordering that conduct, our government will adopt these methods again in the future," said Anthony Romero, executive director of the American Civil Liberties Union.
Obama has condemned the torture, but has refused to say whether he thinks it is sometimes effective.
- Bush in the loop? -
White House spokesman Josh Earnest refused a "yes or no" question as to whether Obama believes that torture saves lives.
"The most important question is: Should we have done it? And the answer to that question is 'no'," he said.
"The president does not believe that the use of enhanced interrogation techniques was good for our national security."
According to the report, Bush only learned details of it in 2006, four years after it started in the wake of the 9/11 attacks.
But, speaking to Fox News, former vice president Dick Cheney denied Bush was kept out of the loop.
He said the then-president "was in fact an integral part of the program and he had to approve it."
Detainees were beaten, waterboarded -- some of them dozens of times -- and humiliated through the painful use of medically unnecessary "rectal feeding" and "rectal rehydration".