WASHINGTON (CNN) - House Speaker Nancy Pelosi, who has denied she was ever told explicitly that waterboarding had been used on terrorist suspects, "has a lot of explaining to do," former Speaker Newt Gingrich said Sunday.
Gingrich, who held the House post from 1995 to 1999, said Pelosi keeps changing her statements on how much she knew about the practice and when.
In the interest of national security, "she [Pelosi] has a responsibility to say nothing or tell the truth," he told "Fox News Sunday." "In this case, it's clear she wasn't telling the truth."
A CIA memo provided to CNN by Republican sources lists 40 briefings for members of Congress from September 2002 to March 2009.
The first briefing - on September 4, 2002 - was for then-House Intelligence Committee Chairman Porter Goss and Pelosi, then the ranking Democrat on the committee.
The subject of the briefing is listed as "EITs," or enhanced interrogation techniques, "including use of EITs on Abu Zubaydah," a suspected al Qaeda leader imprisoned at U.S. facilities in Guantanamo Bay.
One of those techniques is waterboarding, which simulates drowning and which has been described by critics as torture.
Initially, Pelosi said she had not been briefed on EITs, according to the memo provided to CNN by Republican sources.
However, a recently declassified Justice Department memo from 2005 says, "The CIA used the waterboard 'at least 83 times during August 2002' in the interrogation of Zubaydah."
That was before the September 4 Pelosi-Goss briefing.
Pelosi released a statement in December 2007 that said, "I was briefed on interrogation techniques the administration was considering using in the future. The administration advised that legal counsel for both the CIA and the Department of Justice had concluded that the techniques were legal."
Last month, Pelosi told reporters she was told about the legal justification for the interrogation techniques, including waterboarding, but was never told the technique had been used on any detainees.
"We were not - I repeat - were not told that waterboarding or any of these other enhanced interrogation methods were used," she said Friday.
In a statement issued Friday, Pelosi said: "Of the 40 CIA briefings to Congress reported recently in the press, I was only briefed once, on September 4, 2002, as I have previously stated."