Seeking information about the detention of terrorism suspects, abuse of detainees and government secrecy, Democrats on the Senate Judiciary Committee are reviving dozens of demands for classified documents that until now have been rebuffed or ignored by the Justice Department and other agencies.

"I expect real answers, or we'll have testimony under oath until we get them," said Senator Patrick Leahy, who will head the committee beginning in January when the Democrats take over leadership of the Senate.

"We're entitled to know these answers," the Vermont Democrat said in an interview, "and in many instances we don't get them because people are hiding their mistakes. And that's no excuse."

Leahy, who had said little about his plans for the committee, expressed hope for greater cooperation from the Bush administration, which he described as having been "obsessively secretive." His aides have identified more than 65 requests he has made to the Justice Department or other agencies in recent years that have been rejected or permitted to languish without reply.