WASHINGTON (Reuters) - U.S. President Donald Trump's administration has begun returning to Congress copies of a voluminous 2014 report describing the CIA's harsh detention and interrogation programs, U.S. officials said on Friday.

The Trump administration's move means it could be more difficult for the full, 6,700-page report to be made public, because documents held by Congress are exempt from laws requiring government records to eventually be made public.

The White House made the move in response to requests by Sen. Richard Burr, the Senate Intelligence Committee's current Republican chairman, officials said.

In a statement emailed to Reuters, Burr said: "I have directed my staff to retrieve copies of the Congressional study that remain with the Executive Branch agencies and, as the Committee does with all classified and compartmented information, will enact the necessary measures to protect the sensitive sources and methods contained within the report."

Sen. Dianne Feinstein, the Democrat who chaired the committee when the report was produced, had asked that it be distributed to multiple executive branch agencies, a move designed to make it eventually releasable to the public under the Freedom of Information Act law.

Feinstein said in a statement that she was "concerned and disappointed" that Burr requested that the document be returned, calling it a departure from the committee's normal bipartisan nature.

"No senator, chairman or not, has the authority to erase history. I believe that is the intent of the chairman in this case," she said.

Sen Mark Warner, who succeeded Feinstein as the committee's top Democrat, said in a Twitter post he was "disappointed" with Burr's decision, and that the report "must be preserved so we can learn from past mistakes & ensure that abuses are never repeated."

A declassified executive summary of the report was made public in December 2014. It concluded that the CIA's interrogation programs, using techniques such as waterboarding that most observers consider torture, were more brutal and less effective than the CIA had told policymakers.

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The report said that not a single terrorist attack was foiled as a result of the use of harsh interrogation techniques.

The American Civil Liberties Union had filed litigation to have the full report released. But U.S. courts ruled that because the document was created by Congress, it was exempt from the Freedom of Information Act.

At least one copy of the report, however, will not be returned to the committee. That’s because a copy has been preserved in former President Barack Obama’s presidential archive, according to a Dec. 9, 2016 letter written to Feinstein by Obama’s top White House lawyer at the time, W. Neil Eggleston.

The CIA declined to comment. Burr's move was first reported by the New York Times.

(Reporting by Mark Hosenball and Jonathan Landay; Writing by Warren Strobel; Editing by Bernadette Baum)