WASHINGTON  -- A top House Democrat raised new questions Tuesday about the accuracy of the CIA's account of congressional briefings on severe interrogation techniques. He said a staff aide the agency listed as attending a 2006 briefing was instead barred from it. 

House Appropriations Committee Chairman David Obey of Wisconsin said in a May 18 letter to CIA Director Leon Panetta that a committee aide, Paul Juola, was listed as being in a Sept. 19, 2006, briefing on the full detainee program, including 13 enhanced interrogation techniques. 

But according to Obey, Juola said he walked members to the briefing room, but was told by then-CIA Director Michael Hayden and another CIA official that he could not attend. Reps. Bill Young, R-Fla., and John Murtha, D-Pa., are listed by the CIA as attending the briefing, though Murtha left before the discussion of interrogation techniques. 

The steady drip of information about CIA briefings to Congress has clouded questions of who in Congress knew what and when about the harsh interrogation techniques used on two dozen CIA prisoners. Three detainees underwent waterboarding, a form of simulated drowning that President Barack Obama has called torture. 

A CIA list of 40 congressional briefings for legislators and staffers was turned over to Congress two weeks ago. 

The list was made available after House Speaker Nancy Pelosi, D-Calif., was accused by critics of not speaking out during the briefings against the harsh techniques and then suggested that she was never told about the use of the methods by CIA briefers. 

The CIA list has been cited by Pelosi's critics as evidence that she attended one 2002 briefing where waterboarding and other harsh methods were discussed. Pelosi has said the briefers at that session described waterboarding, and said they had legal opinions approving it but that it had not been used at that time. Last week, she accused the CIA briefers of misleading her, but later issued a statement that shifted the blame to the Bush administration. 

Other House officials say the CIA list contains more errors but would not describe them, claiming the attendance information was classified because it is based on secret transcripts of the meetings. 

CIA spokesman Paul Gimigliano acknowledged Tuesday that the list may not be accurate. 

"As the agency has pointed out more than once, its list compiled in response to congressional requests reflects the records it has. These are notes, memos, and recollections, not transcripts and recordings." 

Michael Steel, a spokesman for House Republican leader Rep. John Boehner of Ohio, dismissed Obey's complaint about the list's accuracy on Tuesday and criticized Pelosi for saying the CIA misled members of Congress without proof. 

"Chairman Obey's complaint is beside the point. The Speaker accused our intelligence professionals of lying to her. Where's her evidence to back up this charge? If she doesn't have any, she should apologize to these men and women who spend their lives protecting this country," Steel said. 

Pelosi has been a frequent target of criticism from Republicans who are eager to argue that Democrats knew about waterboarding and did little to stop it.