In addition to the discussion about the U.S. drone program, senators questioned CIA director-designate John Brennan on Thursday about the agency’s use on al-Qaida detainees of waterboarding, sleep deprivation and other harsh interrogation practices that many experts consider torture and which were adopted after the Sept. 11, 2001, attacks. At the time, Brennan was a senior CIA executive.

Brennan reiterated that while he was aware of the program, he was not involved in it and wasn’t in a position to stop the practices. He said he had raised his “personal objections” in conversations with other top officials.

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.”

He declined several times to describe waterboarding as torture, but he agreed that it is “reprehensible and something that should not be done.” Obama banned the procedure and other harsh interrogation techniques after he took office in 2009.