WASHINGTON (Reuters) - The White House chief of staff faced possible contempt charges after a congressional panel on Thursday ruled as invalid President George W. Bush’s bid to limit the probe of the firing of federal prosecutors.

White House chief of staff Joshua Bolten speaks during a press briefing at the Eisenhower Executive Office Building in Washington, February 7, 2005. Bolten faced possible contempt charges after a congressional panel on Thursday rejected President George W. Bush's attempt to limit the probe of the firing of federal prosecutors. REUTERS/Larry Downing

On a party-line vote of 7-3, a Democratic-led House of Representatives Judiciary subcommittee rejected Bush’s contention that his claim of executive privilege shields the top aide, Joshua Bolten, from having to turn over subpoenaed documents.

“Those claims are not legally valid,” said panel Chairwoman Linda Sanchez, a California Democrat.

Sanchez said she hoped the White House would yield and produce the documents, but the administration accused Congress of pushing for a courtroom showdown.

The administration says its firing of nine of the 93 U.S. attorneys last year were justified. But critics say the ousters were politically motivated, perhaps even to influence ongoing criminal probes of Democratic or Republican lawmakers.

“We are hopeful that the White House will come to the conclusion that it is better for them to cooperate than continue this confrontation,” Sanchez said.

Last week the panel moved toward contempt proceedings against former White House counsel Harriet Miers after she declined to appear at a hearing. It rejected Bush’s claim that Miers did not have to show up.

White House spokesman Tony Fratto said, “It’s unfortunate that the committee continues down this path, rather than accepting our offer of accommodation.”

“It’s no wonder that the committee is less successful at getting facts than headlines,” Fratto added. “That a president should be able to receive candid and confidential advice from his aides rests on solid legal ground.”

While the White House has refused to provide documents, it has offered to permit former and current aides to talk with lawmakers behind closed doors -- but without a transcript and not under oath. Democrats say that is unacceptable.

Over the years with other administrations, most such disputes between the legislative and executive branches of government have ended in compromise.

If this one does not, the full House Judiciary Committee could vote to hold Bolton and Miers in contempt of Congress. If the entire House concurs, the case would be referred to a U.S. attorney to seek grand jury indictment.