It also is providing fresh ammunition for Democratic criticism of President Bush's Iraq policy and threatening to widen a White House-CIA rift.
White House officials on Monday vigorously denied that they played any role in disclosing the identity of a CIA operative whose husband, former ambassador Joseph Wilson, has challenged Mr. Bush's claims of Iraq's weapons of mass destruction.
At issue is whether White House officials deliberately leaked the name to syndicated columnist Robert Novak and other selected journalists last July in retaliation, and in an attempt to blunt Wilson's criticism.
Novak wrote that he got the name from "two senior administration officials." The Washington Post reported that a White House official called six reporters with the agent's name.
Federal law makes it a crime for anyone to disclose the identity of covert U.S. intelligence officers. Senior White House Correspondent John Roberts reports both the FBI and the Justice Department's counterespionage division are now investigating the leak.
The White House said that leaking classified information was a serious matter that should be "pursued to the fullest extent" by the Justice Department. White House officials, at their senior staff meeting, were urged to contact the Justice Department if they had relevant information, officials said.
But White House officials denied it leaked the CIA officer's identity.
"There's been nothing, absolutely nothing brought to our attention to suggest any White House involvement, and that includes the vice president's office as well," spokesman Scott McClellan said.
In particular, McClellan said it was "ridiculous" to suggest that Karl Rove, Mr. Bush's top political operative, was involved, as Wilson once charged. "He wasn't involved," McClellan said of Rove. "The president knows he wasn't involved … It's simply not true."
Democrats on Monday demanded appointment of an independent counsel to investigate. Four Senate Democrats, including Minority Leader Tom Daschle, D-S.D., urged Attorney General John Ashcroft to appoint a person of "unquestioned independence and impartiality."
"We do not believe that this investigation of senior Bush administration officials…can be conducted by the Justice Department because of the obvious and inherent conflicts of interests involved," said the letter, also signed by Sens. Carl Levin, D-Mich., Joseph Biden, D-Del. and Jay Rockefeller, D-W.Va.
But McClellan argued that the Justice Department "is the appropriate agency to look into matters like this."
Ashcroft has never appointed a special counsel. The rules for naming one give Ashcroft wide latitude to either appoint one outright, conduct a preliminary investigation to determine if such a counsel is needed, or to conclude that it would be better for the Justice Department to handle the probe itself.
For their part, Justice Department lawyers must answer a long list of questions before determining whether to initiate a full-blown criminal probe. There is no deadline.
The CIA complaint is only one of about 50 the Justice Department receives each year from the spy agency about leaks of classified information. Very few ever get beyond a preliminary investigation.
Controversy over the leak could complicate the administration's efforts to persuade Congress to provide $87 billion for Iraq and Afghanistan and other nations to contribute cash and troops. The administration already faced criticism over its claims that Iraq harbored weapons of mass destruction; none have been found.
The incident is also providing another potential irritant to the strained relationship between the Bush White House and the CIA, whose director, Tenet, is a holdover from the Clinton administration.
In 2002, the CIA sent Wilson, a former ambassador to Gabon, to Africa on a secret mission to evaluate reports of the alleged Iraqi uranium purchases. He reported back privately that he had been unable to substantiate them.
Last July, Wilson went public, airing his doubts in a newspaper opinion piece.
About a week later, Novak printed the name and occupation of Wilson's wife as a CIA analyst on weapons-proliferation issues and suggested the trip to Africa was her idea.
After Novak's column was published, the CIA's Office of General Counsel sent a letter to the Justice Department, saying that a violation of the law had apparently occurred when someone provided the CIA officer's name. The letter was not signed by Tenet and did not call for a specific investigation of the White House.
Previously, the CIA sought to distance itself from Mr. Bush's assertion in his January State of the Union address that Saddam Hussein was shopping in Africa for "significant quantities" of uranium ore for use in atomic weapons.
Tenet had questioned the veracity of that allegation, based on a discredited British intelligence report, and had argued against including the passage in the president's speeches. Administration officials later acknowledged the error.
Novak said Monday on CNN that "nobody in the Bush administration called me to leak this."
He said he learned the operative's identity while he was interviewing "a senior administration official." The CIA confirmed the information, Novak said, and "asked me not to use her name but never indicated it would endanger her or anybody else."
He added, "Mrs. Wilson was an analyst, not a spy or a covert operative and not in charge of covert operatives." He attributed all the fuss over the incident to "pure Bush bashing. There's no great crime involved here," he said.
Wilson backtracked Monday, saying he had not meant to imply that Rove "was the source or the authorizer, just that I thought that it came from the White House, and Karl Rove was the personification of the White House political operation."
But Wilson also said in a telephone interview that "I have people who I have confidence in, who have indicated to me that he (Rove), at a minimum, condoned it and certainly did nothing to put a stop to it for a week after it was out there."