WASHINGTON —  A federal judge dealt a setback to the Bush administration on its warrantless surveillance, ordering the Justice Department on Thursday to release documents about the program within 20 days or to compile a list of what it is withholding.

U.S. District Judge Henry Kennedy said a private group will suffer irreparable harm if the documents it has been seeking since December are not processed promptly under the Freedom of Information Act.

The Justice Department failed to meet the time restraints under FOIA and failed to make a case that it was impractical to deal quickly with the request by the Electronic Privacy Information Center.

Justice Department spokesman Charles Miller said no determination has been made as to what the government's next step will be.