CIA Director John Brennan has denied that his agency has hacked into lawmakers' computers, as the chairman of the Senate Intelligence Committee has charged. The dispute, made public on Tuesday, has been going on for years.
In 2002, shortly after the U.S. invaded Afghanistan, the CIA began to detain and interrogate terror suspects.
Several years later, the Senate Intelligence Committee began investigating charges that the spy agency used torture in those interrogations.
In 2009, the CIA let congressional investigators use its computers to review top-secret documents.
But Intelligence Committee Chairwoman Dianne Feinstein said Tuesday the agency illegally monitored the staffers' work, and in 2010 withdrew their access to the documents.
"In short, this was the exact sort of CIA interference in our investigation that we sought to avoid at the outset," said Feinstein.
Senator Feinstein raised concerns that the CIA's alleged actions jeopardized the Senate's independence and its ability to conduct oversight of government agencies.
"I have grave concerns that the CIA's search may well have violated the separation of powers, principles embodied in the United States Constitution," said Feinstein.
The CIA says Senate aides investigating the agency's secret interrogation and detention program illegally took classified documents.
CIA Director John Brennan said the agency was not trying to stop the committee's report.
"As far as the allegations of, you know, CIA hacking into, you know, Senate computers, nothing could be further from the truth. We wouldn't do that. I mean, that's just beyond the scope of reason, in terms of what we do," said Brennan.
At the White House, spokesman Jay Carney did not take sides, saying the matter is being reviewed.
"You saw the CIA director say today that if there was any inappropriate activity by the CIA or staff, he would, of course, want to get to the bottom of it, and certainly, the president would agree with that," said Carney.
The committee's 6,300-page report has not been released to the public. Lawmakers say it details the CIA's use of waterboarding and other extreme techniques during the Iraq and Afghanistan wars.
The four-year, $40 million study also reportedly said the CIA misled the president, Congress and the public about the value of the intelligence yielded by the program.
Editor's Note: An earlier version of this story incorrectly indicated that CIA Director John Brennan specifically denied the CIA searched Senate computers.