"We have cooperated closely with the Justice Department throughout its review, and we will continue that cooperation with the Special Counsel," said Richard Sauber, an attorney for the president, in a statement.

"We are confident that a thorough review will show that these documents were inadvertently misplaced, and the President and his lawyers acted promptly upon discovery of this mistake," he said.

(Reporting by Jeff Mason; Editing by Chizu Nomiyama)