She said the account had been provided by a staff member who attended the briefing. She did not speak out at the time due to secrecy rules, and so was not complicit in any abuse of detainees, she said.

“The speaker’s comments continue to raise more questions than provide answers,” said Representative John A. Boehner of Ohio, the Republican leader. “It’s pretty clear that they were well aware of what these enhanced interrogation techniques were; they were well aware that they’d been used; and it seems to me that they want to have it both ways. You can’t have it both ways.”

Other Republicans have sought to drive the point home, suggesting that Ms. Pelosi tacitly supported the interrogation techniques in the aftermath of the Sept. 11 attacks but sought to back away when disclosures about mistreatment of detainees shifted public opinion.

“We know that if the C.I.A. proposes something that we believe is wrong, we could do something about it,” Senator Christopher S. Bond, Republican of Missouri, a senior member of the Senate Intelligence Committee, said Thursday. “We’ve done things about it and it’s no excuse to say that I was powerless.”

Ms. Pelosi said she had supported a letter opposing the tactics sent in 2003 by Representative Jane Harman of California, who replaced Ms. Pelosi as the top Democrat on the panel when Ms. Pelosi took over as Democratic leader. But she said that she realized a letter would not change administration policy and that she instead set about to win Democratic control of Congress.

“It was clear we had to change the leadership in Congress and in the White House,” she said. “That was my job  the Congress part.”

To resolve the dispute about what was said during the September 2002 meeting, Ms. Pelosi has urged the C.I.A. to disclose the contents of that session. But that appears doubtful because the agency has rebuffed a request by former Vice President Dick Cheney for two memorandums that Mr. Cheney says would demonstrate the effectiveness of harsh interrogation methods in obtaining information from captured operatives of Al Qaeda.