The Justice Department is violating federal disclosure law by failing to provide information about its role in the Bush administration's domestic spying program, a civil liberties group said Wednesday.

The government has yet to comply with requests filed Dec. 16 by the Electronic Privacy Information Center under the Freedom of Information Act, hours after the existence of the National Security Agency's warrantless eavesdropping was made known.

The group expects to file a FOIA lawsuit Thursday in U.S. District Court in Washington, asking a judge to order the department to release documents within 20 days because the information "concerns a matter of extraordinary public interest."

Meanwhile, the nonpartisan Congressional Research Service said Wednesday that the administration's limited congressional briefings on the monitoring "appear to be inconsistent with the law."

The CRS memo backs the contention of California Rep. Jane Harman, the senior Democrat on the House intelligence committee, that all the members of the intelligence oversight committees are entitled to hear closed-door explanations of the program.

Administration officials have, to date, briefed only the "Gang of Eight," which is made up of the top Republicans and Democrats in the House and Senate and on the intelligence panels. This smaller group is scheduled to receive another briefing on the NSA program on Friday, said two congressional aides, speaking on condition of anonymity because the briefing has not been publicly announced.

In the FOIA matter, EPIC asked four Justice Department officials to release quickly any department audits of the NSA program, writings on the subject by government lawyers, a checklist to help decide whether there is a legal basis to monitor an individual's communications and documents discussing the use of information obtained through the NSA program to obtain a warrant from a secret federal court for more eavesdropping.

The Justice Department sent EPIC a reply within three business days of its requests, saying they would be handled expeditiously but would take more than 30 business days to fulfill.

EPIC said the public needs the information now because of the lively national debate over the legality of the NSA program and in advance of a Feb. 6 Senate hearing at which Attorney General Alberto Gonzales is expected to testify.

President Bush last month acknowledged he had ordered the surveillance, bypassing the secret Foreign Intelligence Surveillance Court, and said the Justice Department regularly reviewed the program to make sure it stayed within the law.

Gonzales also has repeatedly defended its legality in the face of questions from Democratic and Republican lawmakers and legal scholars about whether the president has the authority to order monitoring of people in the United States without a court's approval.

Two separate lawsuits challenging the legality of the spying program were filed Tuesday in Detroit and New York by the American Civil Liberties Union and the Center for Constitutional Rights.