WASHINGTON  Attorney General Alberto Gonzales reached into the ranks of U.S. attorneys for an interim chief of staff Friday to replace Kyle Sampson, who resigned earlier this week for his role in the Justice Department's abrupt dismissal of eight federal prosecutors.

Gonzales named Chuck Rosenberg, the chief federal prosecutor for the Eastern District of Virginia in Alexandria, to serve as his closest advisor at a time when several Democrats and some Republicans in Congress have called for the attorney general to resign over his handling of prosecutors' firings.

Rosenberg was chief of staff to former deputy attorney general James Comey. Other previous jobs included counselor to former attorney general John Ashcroft and counsel to FBI Director Robert Mueller.

Meanwhile, the Democrat-controlled Senate and House Judiciary committees continued to press for the testimony of several White House officials in their investigations of the matter.

At the top of that list of possible witnesses is White House political strategist Karl Rove, whose name surfaced Thursday in recently-disclosed e-mails in which he inquired in January 2005 about the administration's replacement plan for U.S. attorneys.

Until the e-mail was made public, the White House had maintained that the idea for removing the prosecutors started with former White House counsel Harriet Miers, but the administration has since backed away from that contention. On Friday, White House spokesman Tony Snow was unable to say who initiated the plan and when.

"The story keeps changing, which neither does them or the public any good," Sen. Chuck Schumer, D-N.Y., said Friday. "They ought to gather all the facts and tell the public the truth."

Congressional subpoenas could come as early as next week, when the Senate is expected to bring up a bill that would remove a provision in the Patriot Act that allows the attorney general to replace U.S. attorneys without Senate confirmation.

The Senate Judiciary Committee has scheduled a vote for next Thursday on authorizing subpoenas for Rove, Miers and her deputy, William K. Kelley. The panel already has approved the use of subpoenas, if necessary, for Justice Department officials and J. Scott Jennings, a White House aide who works in Rove's office.

Meanwhile, a Republican House member suggested it might be time for Gonzales to go.

"It is ultimately the president's decision, but perhaps it would benefit this administration if the attorney general was replaced with someone with a more professional focus rather than personal loyalty," said Rep. Dana Rohrabacher, R-Calif. He complained of "a pattern of arrogance in this administration."

Other GOP lawmakers have joined Democrats in harsh indictments of Gonzales' effectiveness but have stopped short of saying he should be fired.

"I do not think the attorney general has served the president well, but it is up to the president to decide on General Gonzales' continued tenure," said Sen. Susan Collins, R-Maine.

Contributing: Associated Press