The Bush administration endorsed the use of waterboarding against al-Qaeda suspects in secret memos to the Central Intelligence Agency (CIA), the Washington Post has reported.
The pair of classified memos, written in 2003 and 2004, were requested by George Tenet, former CIA chief, more than a year after secret interrogations got under way, the newspaper quoted administration and intelligence officials as saying.
The Post reported on Wednesday that the CIA required cover from the White House due to concerns of a possible backlash if details on harsh interrogation methods went public.
Waterboarding, which involves tipping a suspect back and pouring water over his face to provoke the fear of drowning, has been roundly criticised by human rights groups.
Although lawyers from the US justice department had permitted the agency's interrogation methods, which began in 2002, senior CIA officials wanted the Bush administration to give the programme an endorsement in writing, the Post reported.
The request by Tenet to get a written endorsement of the CIA programme reflected unease that the Bush administration might absolve itself of decisions taken about the handling of captured al Qaeda leaders, the Post said, citing anonymous former intelligence officials.
Tenet first asked the White House for written approval in June 2003 during a meeting with members of the National Security Council, the Post reported.
Soon after, Tenet received a brief memo from the Bush administration, giving explicit approval for the CIA's interrogation methods, the officials were cited as saying by the Post.
Tenet requested a second endorsement of CIA interrogation from the administration in June 2004, the newspaper reported.
The request was made after the abuse of Iraqi detainees by US soldiers at Baghdad's Abu Ghraib prison became public, it said.
Administration officials confirmed the existence of the memos, but neither they nor former intelligence officers would describe the still classified documents in detail, the newspaper reported.