President Bush is expected to claim executive privilege to prevent two more White House aides from testifying before Congress about the firings of federal prosecutors.

Thursday is the deadline for Karl Rove, Bush's top political adviser, to provide testimony and documents related to the firings, under a subpoena from the Senate Judiciary Committee. Also subpoenaed was White House political aide J. Scott Jennings. The Justice Department included both men on e-mails about the firings and the administration's response to the congressional investigation.

White House Counsel Fred Fielding has consistently said that top presidential aides — present and past — are immune from subpoenas and has declared the documents sought off-limits under executive privilege.

The House Judiciary Committee already has approved a contempt citation against two other Bush confidants, chief of staff Josh Bolten and former White House counsel Harriet Miers. The full House is expected to vote on the citation in the fall, but the Justice Department has said it won't prosecute the two.

Sara Taylor, the former White House political director, appeared before the Senate Judiciary Committee last month and sought to answer some lawmakers' questions and remain mum on others, citing Bush's claim of privilege.