Washington: President Barack Obama will not declassify a comprehensive Senate report on the CIA’s use of torture but he will preserve a copy in his presidential library, according to a White House letter released on Monday.

Obama stipulated that the material remain classified for 12 years, said the letter from White House Counsel Neil Eggleston to Senator Dianne Feinstein, vice chair of the Senate Intelligence Committee.

Amid worries the incoming Trump administration could move to have all copies of the report destroyed, Eggleston said that the full 6,700-page study will be preserved under the Presidential Records Act.

‘At this time, we are not pursuing declassification of the full study,’ the letter said.

The Committee Study of the Central Intelligence Agency’s Detention and Interrogation Program, completed in 2014, detailed brutal torture methods like waterboarding used by the agency on detainees following the September 11, 2001 attacks.

It also reportedly deeply questioned the effectiveness of the techniques, since banned by the Obama administration.

Several copies were distributed to key parts of the US intelligence community, which has kept them under wraps.

In 2015, when Republicans took the lead of the Intelligence Committee, the new Chair Richard Burr sought to collect them all back.

Since then, some Democrats have pressed for the release of the full report, fearing Republicans aim to destroy it.

Obama’s move guarantees at least one copy will survive, if not made public before 2029.

Senator Ron Wyden, a Democratic member of the committee, urged Obama to put the classified study on the public record and to direct that a redacted version be declassified, pointing to the possibility that President-elect Donald Trump could revive the use of torture.

‘President Obama has made his opposition to torture a central part of his legacy,’ Wyden said in a statement.

‘The American people deserve the opportunity to read this history rather than see it locked away in a safe for 12 years.

‘It is also more critical than ever that the study be made available to cleared personnel throughout the federal government who are responsible for authorising and implementing our country’s detention and interrogation policies,’ Wyden said.