Brennan, 57, is a veteran of more than three decades in intelligence work. He withdrew his name from nomination to head the CIA four years ago amid questions about the role he played at the CIA when the Bush administration approved waterboarding and other forms of "enhanced interrogation" of suspected terrorists.
On the question of waterboarding, Brennan said that while serving as a deputy manager at the CIA during the Bush administration, he was told such interrogation methods produced "valuable information." Now, after reading a 300-page summary of a 6,000-page report on CIA interrogation and detention policies, he said he does "not know what the truth is."
Brennan bristled once during the day, when he was questioned about leaks to the media about an al-Qaida plot to detonate a new type of underwear bomb on a Western airline.
Sen. James Risch, R-Idaho, accused him of having leaked classified information in a telephone call with former government officials who were preparing to make television appearances to explain the plot.
"I disagree with that vehemently," the nominee shot back.
On May 7 of last year, The Associated Press reported that the CIA thwarted an ambitious plot by al-Qaida's affiliate in Yemen to destroy a U.S.-bound airliner, using a bomb with a sophisticated new design. The bombing would have taken place near the anniversary of the killing by U.S. Navy SEALs of Osama bin Laden. The next day, The New York Times and the Los Angeles Times reported that the would-be bomber was cooperating with U.S. authorities.
Risch and Sen. Dan Coats of Indiana were among those who contended Brennan inadvertently had revealed that the U.S. had a spy inside Yemen's al-Qaida branch when, hours after the first AP report appeared, he told a group of media consultants that "there was no active threat during the bin Laden anniversary because ... we had inside control of the plot."
Brennan won praise from several members of the committee as the day's proceedings drew to a close.
"I think you're the guy for the job, and the only guy for the job," said Sen. Jay Rockefeller, D-W.Va.
The panel will meet in closed session next week to discuss classified material.
Associated Press writers Julie Pace, Lara Jakes, Donna Cassata and David Espo contributed to this report.
Follow Kimberly Dozier on Twitter: http://twitter.com/KimberlyDozier
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