WASHINGTON — A Senate panel found former presidential adviser Karl Rove and current White House Chief of Staff Joshua Bolten in contempt of Congress on Thursday for refusing to testify and turn over documents in the investigation of the firings of nine U.S. attorneys last year.

The Senate Judiciary Committee approved contempt citations against Rove and Bolten on a 12-7 vote, rejecting the White House position that the work of two of Bush's closest advisers is covered by executive privilege.

Earlier this year, the House Judiciary Committee cited Bolten and former White House counsel Harriet Miers for contempt. But action by either chamber of Congress is still weeks or months away. Lawmakers and aides said neither house will take up the issue until late January at the earliest.

More than six months ago, the Senate Judiciary Committee requested Rove's public testimony on the firings of the prosecutors and issued subpoenas for internal White House e-mails, memos and other related documents. As custodian of White House documents, Bolten was cited for his refusal to turn them over.

"White House stonewalling is unilateralism at its worst, and it thwarts accountability. Executive privilege should not be invoked to prevent investigations into wrongdoing," said Senate Judiciary Committee Chairman Patrick Leahy, D-Vt.

Two senior Republicans, Sens. Arlen Specter, R-Pa., and Charles Grassley, R-Iowa, supported the contempt charges.

The White House on Thursday repeated its offer to allow Rove and other current and former senior aides to testify about the firings behind closed doors, not under oath and with no transcript. White House press secretary Dana Perino said the Justice Department would refuse to convene a grand jury if either the full House or the full Senate approved the contempt citations; that would leave Democrats unable to force the question of the limits of executive privilege into the federal courts.

"The constitutional prerogatives of the president would make it a futile effort for Congress to refer contempt citations," Perino said.

The contempt vote came a year after seven of the prosecutors were removed on one day. The firings provoked a furor on Capitol Hill and led to the resignation of former attorney general Alberto Gonzales. Former U.S. Attorney David Iglesias of New Mexico was among the prosecutors fired.

The Justice Department's inspector general and its Office of Professional Responsibility are conducting an internal investigation of the firings and whether Gonzales obstructed congressional probes of the matter.

Despite the likely need for 60 votes to cut off a GOP filibuster in the Senate, Majority Leader Harry Reid, D-Nev., said he would "look very favorably" on forcing a roll call vote on the issue. "We'll take a look at that when we come back in January," Reid said.