By Mark Mazzetti

New York Times News Service

WASHINGTON — The chairwoman of the Senate Intelligence Committee on Tuesday accused the CIA of improperly removing documents from computers that committee staff members had been using to complete a report on the agency’s detention program, saying the move was part of an effort to intimidate the committee.

Sen. Dianne Feinstein, D-Calif., said on the Senate floor that the agency had violated federal law and undermined Congress’ constitutional right to oversee the actions of the executive branch.

“I am not taking it lightly,” she said.

John Brennan, the CIA director, denied Feinstein’s assertions.

“We wouldn’t do that,” Brennan said in response to questions from NBC’s Andrea Mitchell in an appearance at the Council on Foreign Relations in Washington.

“We weren’t trying to block anything,” Brennan said. “The matter is being dealt with in an appropriate way.”

He added that the CIA was in no way spying on the committee or the Senate.

He referred to inquiries now underway by the CIA’s inspector general and the Justice Department, and urged Senate critics to wait for the results of those reviews.

Feinstein leveled the new charge as part of a lengthy public recounting of the years of jousting between her committee and the CIA over the legacy of the detention program, which President Barack Obama officially ended in January 2009.

The disclosure comes a week after the first reports that the CIA late last year had carried out a separate search of computers used by her staff. The CIA said it carried out the search to uncover how the committee gained access to an internal review of the detention program cited by Democratic lawmakers critical of the program.

Calling the present conflict a “defining moment” for the oversight of U.S. spy agencies, Feinstein denied that committee staff members had obtained the internal review improperly. She said that the internal document had been made available as part of the millions of pages of documents that the agency had given the committee to conduct its investigation.

The CIA has referred the matter to the Justice Department to investigate possible wrongdoing, a move that Feinstein called “a potential effort to intimidate this staff.”

Brennan challenged the committee to issue its report — parts of which he said he disagreed with — but he also said, “I will protect sources and methods.”

In her speech, Feinstein for the first time revealed that in 2010 the CIA had removed documents from the computer system used by her staff at an agency facility in Northern Virginia, where the intelligence committee was working on its investigation.

Feinstein said she had sought an apology and an acknowledgment that the CIA’s conduct was improper.

“I have received neither,” she said.

It was unclear Tuesday what specific documents were removed in 2010.