Lawyers for a former top aide to Vice President Dick Cheney told a federal judge Friday they want to subpoena journalists and news organizations for documents they may have related to the leak of a CIA operative's name.

In a joint filing with prosecutors, lawyers for I. Lewis "Scooter" Libby, 55, warned U.S. District Judge Reggie B. Walton that a trial likely will be delayed because of their strategy to seek more subpoenas of reporters' notes and other records.

Libby was indicted last year on charges that he lied to FBI agents and a federal grand jury about how he learned CIA operative Valerie Plame's identity and when he subsequently told reporters.

Plame's identity was revealed in July 2003 by columnist Robert Novak after her husband, former U.S. Ambassador Joseph Wilson, accused the Bush administration of twisting intelligence about Iraq's efforts to buy uranium "yellowcake" in Niger. The year before, the CIA had sent Wilson to Africa to determine the accuracy of the uranium reports; he concluded they were untrue.

Special prosecutor Patrick Fitzgerald, in announcing the charges against Libby, portrayed Cheney's former chief of staff as the first government official to have shared Plame's name and her work at the CIA with reporters in the summer of 2003.

Libby's defense team did not disclose the names of reporters or news organizations it wants to subpoena.

The filing provides the most concrete indication yet that a large part of Libby's trial strategy will be identifying other government officials who knew Plame was a CIA operative and told reporters about it.

The kind of subpoena cited is for documents or records, not testimony. Such subpoenas usually require records to be turned over before trial so the defense team would have a chance to review them. Libby's team said it expects a delay in the trial while news organizations fight the subpoenas, if Walton agrees to issue them.

Last summer, several reporters were subpoenaed to testify before a grand jury investigating the leak of Plame's identity. New York Times reporter Judith Miller spent 85 days in jail for refusing to discuss her source.

Lucy Dalglish, executive director of the Reporters Committee for Freedom of the Press, said the defense's strategy is no surprise but still alarming.

"Every key witness in this case is going to be a reporter," Dalglish said. "It's an absolutely ugly situation, ... putting reporters in a very, very bad position, ... and it should send a chill up the spine of American citizens across the country."

The defense attorneys also told Walton that a significant disagreement is brewing between Libby's team and Fitzgerald's prosecutors over whether reporters heard Plame's name from government sources other than Libby.

Libby's lawyers said information about other sources used by reporters is "material to the preparation of the defense."

No trial date has been set. Walton had requested the update on the prosecution's exchange of evidence with the defense before a Feb. 3 hearing in the case.

Fitzgerald said he has turned over 10,150 pages of classified and unclassified documents to Libby's defense team.

But the defense attorneys said they want more. They said they may subpoena other executive branch agencies — besides the special prosecutor's office and the FBI — if Fitzgerald continues to refuse to turn over information he has from those departments. They did not specify which agencies.

Shortly after Libby's indictment, The Washington Post revealed that one of its editors, Bob Woodward, who achieved fame for his reporting on the Watergate scandal during the Nixon administration, may have been the first reporter to learn about Plame.

Woodward gave a sworn deposition to Fitzgerald late last year, telling the special prosecutor that a top administration official told him in mid-June 2003 that Wilson was married to Plame.