The Bush administration found itself on the defensive Monday, after allegations that White House officials leaked the identity of a CIA operative, who is married to a former ambassador critical of intelligence the administration used to justify an attack on Iraq. The CIA director and opposition Democrats are now demanding an investigation into the matter.

At issue is whether anyone in the White House was involved in revealing the identity of a covert CIA operative as a way of punishing the agent's husband, former U.S. Ambassador Joseph Wilson.

Ambassador Wilson angered the administration in July when he publicly challenged the assertion that Iraq had sought to buy uranium in Africa, a claim that was included in the president's State of Union Address in January. The assertion was later discredited by the International Atomic Energy Agency as based on forged documents, and Bush administration officials now say it should not have been included in the speech.

Now, CIA Director George Tenet wants the Justice Department to find out whether someone at the White House leaked the name of Ambassador Wilson's wife to syndicated columnist Robert Novak, who published the information in July. Revealing the identity of a covert intelligence operative is a violation of federal law punishable by up to 10 years in a federal prison.

On Monday, presidential Spokesman Scott McClellan said he is not aware of any White House involvement in the leak, adding "that no one was authorized to do this. That is simply not the way this White House operates." Mr. McClellan also said the White House will cooperate, if the Justice Department decides to launch a full-scale investigation. "The president believes leaking classified information is a very serious matter, and it should be pursued to the fullest extent by the appropriate agency, and the appropriate agency is the Department of Justice," the White House spokesman said.

Mr. McClellan denied an allegation from Ambassador Wilson that the president's senior political adviser, Karl Rove, either was behind the leak, or knew about it.

Ambassador Wilson believes that administration officials allegedly leaked his wife's name to punish him for attempting to undermine the president's case for war against Iraq. "For an administration that came to office promising to restore dignity and honor to the White House, this kind of low blow, even in a bare-knuckled [tough] town like Washington was neither honorable nor dignified," he said.

Democratic presidential candidates and members of Congress are demanding answers on the controversy.

Senator Charles Schumer, a New York Democrat, wants an independent investigation of the matter, apart from the Justice Department. He says there should be serious consequences, if it is proven that White House officials were responsible for the leak.

"[If true], these senior officials have committed a very serious federal crime, all in an effort to discredit her husband, Ambassador Wilson, who was one of the first to question the White House's allegations that Niger sold uranium to Iraq," he said.

On Sunday, both Secretary of State Colin Powell and National Security Adviser Condoleezza Rice told television interviewers that they knew nothing about alleged White House involvement in the leak.

"I know nothing of any such White House effort to reveal any of this, and it certainly would not be the way that the president would expect his White House to operate," said Ms. Rice who appeared on Fox News Sunday.

Ambassador Wilson has become increasingly critical of the administration in recent months, after challenging the assertion that Iraq tried to buy uranium in Africa. Last week, Mr. Wilson appeared at a news conference along with representatives from anti-war groups calling for the dismissal of Defense Secretary Donald Rumsfeld.

"But 9-11 did not give the president and his administration a license to go to war with any nation at any time, based upon some notion that, perhaps, they might someday in the future, if not otherwise dealt with, pose a threat to the region or to us," he said.

Ambassador Wilson retired from the U.S. foreign service in 1998. He was the top U.S. diplomat in Baghdad during the run-up to the Persian Gulf War in 1991.