A federal judge held five reporters in contempt Wednesday for refusing to identify their sources for stories about Wen Ho Lee (search), a former nuclear weapons scientist once suspected of spying, a lawyer said Wednesday.

U.S. District Judge Thomas Penfield Jackson (search) imposed a fine of $500 a day for Associated Press reporter H. Josef Hebert and four others until they comply with his order to reveal the information. The fine will be delayed pending an appeal, according to Nathan Siegel, the AP's lawyer.

The reporters contend they provided all the relevant information they could without defying a commitment to protect their sources.

Lee is seeking the identity of the sources for his lawsuit against the departments of Energy and Justice. He alleges the agencies provided private information on him to reporters and suggested he was a suspect in an investigation into possible theft of secrets from Los Alamos National Laboratory (search) in New Mexico.

In the order, Jackson rejected the reporters' arguments that Lee could obtain the information he seeks elsewhere. He said he was holding the five in contempt because they violated his explicit order.

"The journalists declined to reveal their confidential sources," Jackson said.

Siegel said the AP would appeal.