WASHINGTON -- The federal judges who were bypassed when the Bush administration ordered warrantless wiretaps in the United States received a secret briefing Monday on details of the surveillance.
Separately, a former FBI director and other lawyers questioned whether the surveillance is legal.
The classified briefing at the Justice Department had been requested by U.S. District Judge Colleen Kollar-Kotelly, presiding judge on the Foreign Intelligence Surveillance Act court. Established by Congress in the late 1970s, the court oversees the government's handling of espionage and terrorism investigations.
U.S. District Judge James Robertson last month resigned from the FISA court and other judges voiced concerns about the National Security Agency's electronic surveillance program, which President Bush authorized after the Sept. 11, 2001 terror attacks.
Gen. Michael Hayden, the principal deputy director of national intelligence, was among administration officials who attended the briefing. Hayden served as NSA director when the electronic surveillance program was launched and has since become the government's No. 2 intelligence official.
Details of the program remain highly classified.
Justice Department and NSA spokesmen refused to confirm that a meeting took place. A spokesman for Kollar-Kotelly also declined comment and the nine other FISA judges did not return telephone calls Monday.
But two government officials, speaking on condition of anonymity because of the sensitivity of the issue, confirmed the briefing and Hayden's presence.
In a letter Monday to congressional leaders, 13 legal scholars said the Justice Department's written justification for the NSA monitoring program "fails to offer a plausible legal defense."
In a five-page letter to House and Senate intelligence committee leaders, Assistant Attorney General William E. Moschella on Dec. 22 outlined a detailed defense for the warrantless surveillance.
He argued that Bush under a congressional resolution passed after the Sept. 11, 2001 terrorist attack, had the authority to order such electronic surveillance as part of his responsibility as commander-in-chief to protect the nation.
But the former government officials and constitutional law experts said Congress did not authorize domestic spying as part of the 2001 resolution. Lawmakers, they wrote, also "indisputably" have the authority to regulate electronic surveillance inside the United States.
The 13 experts said it is "beyond dispute that, in (our) democracy, the president cannot simply violate criminal laws behind closed doors because he deems them obsolete or impracticable."
Legal analysts at the Congressional Research Service last week raised similar questions, and lawmakers have called for hearings on the NSA program.
The group included former federal judge William S. Sessions, who served as FBI director from 1987 to 1993 under President Reagan and President George H.W Bush.
Associated Press writer Katherine Shrader contributed to this report.