CIA Director John Brennan Reuters - Kevin Lamarque (Reuters) - The Central Intelligence Agency misled the U.S. government and public for years about aspects of its brutal interrogation program, concealing details about harsh treatment of detainees and other issues, according to a report in the Washington Post.

U.S. officials who have seen a Senate Intelligence Committee report on the CIA interrogation program described damning new information about a network of secret detention facilities, also called "black sites", the Washington Post said.

The Intelligence Committee is responsible for oversight of the CIA. It completed the 6,300-page draft report on the interrogation program more than a year ago but it remains classified.

At the "black sites", prisoners were sometimes subjected to harsh interrogation techniques even when analysts were sure they had no more information to give, said the report, which the Post said was based on interviews with current and former U.S. officials.

The files reviewed by committee investigators describe previously undisclosed cases of abuse, including the alleged repeated dunking of a terrorism suspect in tanks of ice water at a detention site in Afghanistan. The method bore similarities to waterboarding but never appeared on any Justice Department-approved list of techniques, the Washington Post said.

Officials also said that millions of records show that the CIA's ability to obtain the most valuable intelligence information, including tips that led to the locating and killing of Osama bin Laden in 2011, had little, if anything, to do with "enhanced interrogation techniques", the newspaper said.

A spokesman for the CIA said the agency had not yet seen a final version of the report and was not able to comment, the Washington Post said.

Some current and former agency officials have privately described the study as marred by factual errors and misguided conclusions, the newspaper added.

In March, Senator Dianne Feinstein, who chairs the Senate Intelligence Committee, accused the CIA of searching computers used by committee staffers compiling the report and she questioned whether the agency had broken the law in doing so.

(Reporting by Carey Gillam; Editing by Gareth Jones)