Democrats in control of Congress charged cover-up and demanded investigations into the CIA's destruction of videotapes showing terrorism suspects being subjected to severe interrogation techniques.
The United States has been widely criticized by European allies and human rights groups for methods like "waterboarding" in which prisoners are made to fear that they are drowning.
President George W Bush, who has repeatedly said the United States does not torture, had no recollection of being told about the tapes or their destruction, the White House said.
The CIA's disclosure that it had made and destroyed the tapes plunged the spy agency again into the glare of public scrutiny it has been unable to shake since prewar intelligence on Iraq turned out wrong.
Leading Democrats called for a inquiries by the Justice Department and Congress and criticized the Central Intelligence Agency for acting above the law.
Sen. Edward Kennedy, a Massachusetts Democrat, charged a cover-up reminiscent of the Watergate scandal that drove President Richard Nixon from office in 1974.
"The past six years, the Bush administration has run roughshod over our ideals and the rule of law," Kennedy said in a speech on the Senate floor. "Now, when the new Democratic Congress is demanding answers, the administration is feverishly covering up its tracks."
ABC News, citing unidentified officials, reported that then-White House Counsel Harriet Miers knew about the CIA's plan to destroy the videotapes in 2005 and advised against it.