Republicans charge the timing of the allegations and a threat from President Barack Obama are just political maneuvering to protect House Speaker Nancy Pelosi.
Letters by the chairman of the House Intelligence Committee and other members of the panel say CIA Director Leon Panetta told Congress last month that senior CIA officials have concealed significant actions and misled lawmakers repeatedly since 2001.
Intelligence officials told CBS News the error Panetta briefed Congress about was an error of omission and not deliberate. These members seem to believe there's more to it than that. The timing of all this is no accident.
Exactly what actions Panetta disclosed to the House Intelligence Committee on June 24 is unclear, but committee Chairman Silvestre Reyes, a Texas Democrat, said the CIA outright lied in one case.
"These notifications have led me to conclude that this committee has been misled, has not been provided full and complete notifications, and (in at least one case) was affirmatively lied to," Reyes wrote to Michigan Rep. Peter Hoekstra, the committee's senior Republican. A copy of his letter was obtained by The Associated Press.
Reyes said in the letter that he is considering opening a full investigation.
The ranking Republican on the House Intelligence Committee, Peter Hoekstra, R-Mich., said the flap between Democrats and Panetta is "bizarre" and shows the Democrats lack leadership.
Panetta brought the matters to the committee's attention, CIA spokesman George Little said Wednesday.
"It is not the policy or practice of the CIA to mislead Congress. This agency and this director believe it is vital to keep the Congress fully and currently informed. Director Panetta's actions back that up," Little said. "It was the CIA itself that took the initiative to notify the oversight committees."
Reyes, in a later statement, said: "I believe that CIA has, in the vast majority of matters, told the truth. But in rare instances, certain officers have not adhered to the high standards. ... Both Director Panetta and I are determined to make sure this does not happen again."
Seven Democratic members of the House Intelligence Committee sent a letter to Panetta on June 26 asking that in light of his disclosure he revise a statement he made in May to CIA employees that it was not CIA policy or practice to mislead Congress.
The cryptic letter and CIA statement came on the eve of a House debate on an intelligence bill. The debate is expected to revive a partisan argument that has raged on and off for months about whether House Speaker Nancy Pelosi knew in the fall of 2002 about the CIA's use of waterboarding weeks earlier.
Waterboarding, which simulates drowning, is an interrogation technique the CIA used on three prisoners in 2002 and 2003. Mr. Obama has called waterboarding torture.
Much of the debate on the House intelligence bill is expected to be diverted into a discussion of what Pelosi knew about the CIA's harsh interrogation program and why, if she was briefed on it, she didn't formally object to it.
Republicans on the Intelligence Committee say the letters and Mr. Obama's threat to veto the legislation are cover-up attempts on behalf of Pelosi and what she knew and didn't do about "enhanced interrogation."
"The blatantly political nature of the Democrats' letters is revealed by their handling," said Jamal Ware, spokesman for Republicans on the committee, in a statement late Wednesday.
"One was slipped under a staffer's office door late at night, the other was deliberately hidden from Republican members for two weeks and had to be obtained from the press. It is unfortunate that the president's veto threat and the continued attacks by partisans against the CIA are a direct result of congressional Democrats' continued heavy-handed attempts to cover up for Speaker Pelosi."
Pelosi told reporters in May she had not been informed that waterboarding had been used against terrorism suspects, even though it had been. When asked whether she was accusing the CIA of lying to her, she said, "Yes."
The CIA sent lawmakers a chart in May describing the 40 congressional briefings it gave on the interrogation techniques. But that document was found to include several errors, leaving in question exactly what Pelosi was told.
The Republican Party seized on her accusation that the CIA misled Congress, contending that the California Democrat's remarks have demoralized the intelligence community. House Republicans have repeatedly demanded that a bipartisan panel investigate her allegations.
House Republicans oppose at least one provision in the intelligence authorization bill, and they have an unusual ally: the White House.
Mr. Obama's aides have said they will recommend he veto the bill if it includes a Democratic-written provision requiring the president to notify the intelligence committees in their entirety about covert CIA activities.
Under current law, the president is only obligated to notify the top Democratic and Republican leaders of the House and Senate and the senior Democratic and Republican members on each chamber's Intelligence Committee.
Democrats want to open the briefings to all members of the House and Senate Intelligence committees unless committee leaders agreed otherwise. That would be about 40 lawmakers, depending on shifting membership rosters, instead of the eight required by law.
They claim the Bush administration sought to undermine congressional oversight. However, the White House is concerned that briefing more lawmakers might compromise the most sensitive U.S. intelligence operations.