A federal judge held a reporter in contempt Thursday for refusing to divulge confidential sources to prosecutors investigating the leak of an undercover CIA (search) officer's identity.

U.S. District Judge Thomas F. Hogan (search) ordered New York Times reporter Judith Miller (search) jailed until she agrees to testify about her sources before a grand jury, but said she could remain free while pursuing an appeal. Miller could be jailed up to 18 months.

Hogan cited Supreme Court rulings that reporters do not have absolute First Amendment (searchprotection from testifying about confidential sources. He said there was ample evidence that U.S. Attorney Patrick Fitzgerald of Chicago, the special prosecutor in the CIA leak case, had exhausted other avenues of obtaining key testimony before issuing subpoenas to Miller and other reporters.

"The special counsel has made a limited, deferential approach to the press in this matter," Hogan said.

Fitzgerald is investigating whether a crime was committed when someone leaked the identity of CIA officer Valerie Plame, whose name was published by syndicated columnist Robert Novak on July 14, 2003. Novak cited two "senior administration officials" as his sources.

The Novak column appeared after Plame's husband, former Ambassador Joseph Wilson, was critical in a newspaper opinion piece of President Bush's claim that Iraq sought to obtain uranium in Niger. The CIA had sent Wilson to Niger to investigate that claim, which he concluded was unfounded.

Miller's lawyer, Floyd Abrams, said he would quickly file notice of an appeal of Hogan's ruling with the U.S. Court of Appeals for the District of Columbia Circuit. He and Miller both noted that although she gathered material for a story about Plame, she never wrote one.

"I think it's really frightening when journalists can be put in jail for doing their job effectively," Miller told reporters outside the courthouse.

Fitzgerald also has issued subpoenas to reporters from NBC, Time magazine and The Washington Post. Some have agreed to provide limited testimony after their sources -- notably Lewis "Scooter" Libby, who is Vice President Cheney's chief of staff -- released them from their promise of confidentiality.

Miller and Bill Keller, the Times' executive editor, said they would not agree to provide testimony even under those circumstances.

Novak never has said whether he has been subpoenaed.