James Comey, deputy attorney general, said at a Washington news conference that he would now be the "acting attorney general for this case."
Comey said Ashcroft had suggested the appointment of a special counsel for the case. To fill that position, Comey choose U.S. Attorney for the Northern District of Illinois Patrick Fitzgerald.
The Justice Department has been looking into allegations that someone at the White House told syndicated newspaper columnist Robert Novak the name of a CIA employee.
The CIA officer is the wife of former Ambassador Joseph Wilson, who has been critical of White House's Iraq policies. Wilson, at the request of the CIA, traveled to Africa to look into reports that Iraq was trying to but uranium there. He later disputed that Iraq was trying to buy uranium there.