"I have not foreclosed any options," the attorney general said in his first public comments on the Justice Department's investigation, which is focused on the White House. "This is a matter of great concern to me."

'Valuable' progress

Although Democrats continued to assert that Ashcroft should not oversee an investigation of the Republican administration, the attorney general said "valuable" progress was being made to determine who told newspaper columnist Robert Novak that Valerie Plame Wilson was a CIA officer and the wife of former ambassador Joseph Wilson.

Novak revealed her identity in a column published July 14.

Wilson has accused the administration of disclosing his wife's name in retaliation for his disputing the administration's claim that Iraq tried to buy uranium in Niger for nuclear weapons.

Bush used that argument in building a case for war.

Identifying an undercover CIA operative and leaking classified information are felonies. The maximum penalty is 10 years in prison and $50,000 in fines.

By disclosing her identity, Wilson has said his wife and other associates have been placed at risk of possible harm.

The FBI has begun questioning White House employees as part of the inquiry, which is also expected to extend to the Defense and State departments.

Difficult inquiry

Earlier this month, President Bush expressed doubts that the Justice investigation could identify who identified the CIA officer. Thursday, Ashcroft suggested the inquiry would be difficult because of confidential relationships between news reporters and their sources, but "not impossible."

Sen. Charles Schumer, D-N.Y., a leading advocate for the appointment of special counsel, continued his call Thursday, saying that conflicts of interest involving the attorney general "make it far less likely that the culprit will be found and that justice will be served."

But Justice spokesman Mark Corallo said no person involved in the investigation had "formally or informally" indicated that there are grounds for the attorney general's recusal or for the appointment of a special counsel to take up the inquiry.

"If any person involved in the investigation felt the need for recusal or for a special counsel, the attorney general will get that information and take action," Corallo said.

On the Web

U.S. Attorney General: www.usdoj.gov/ag