The president was interviewed for 70 minutes by U.S. Attorney Patrick J. Fitzgerald, the head of the Justice Department investigation, and by members of his team. The only other person in the room was Jim Sharp, a private trial lawyer and former federal prosecutor hired by Mr. Bush, said White House press secretary Scott McClellan.
"The leaking of classified information is a very serious matter," McClellan said, adding that the president repeatedly has said he wants his administration to cooperate with the investigation. "No one wants to get to the bottom of this matter more than the president of the United States," the spokesman said.
Investigators want to know who leaked the name of Valerie Plame, an undercover Central Intelligence Agency operative, to syndicated columnist Robert Novak last July. Disclosure of an undercover officer's identity can be a federal crime.
Fitzgerald declined, through a spokesman, to comment on the Bush interview, but legal experts following the case said it could indicate the probe was nearing an end.
The investigation has been an embarrassment for a president who promised to bring integrity and leadership to the White House after years of Republican criticism of the Clinton administration.
Four months before the election, the leak controversy has added to Bush's Iraq-related problems. His meeting with the lead investigator came a day before he was to leave on five-day trip to Ireland and Turkey where he was to work to persuade NATO allies to help in Iraq.
Former Ambassador Joseph Wilson, who is married to Plame, has said he believes his wife's identity was disclosed to undermine his credibility. Wilson denounced the Bush administration for claiming that Iraq, under Saddam Hussein, had tried to obtain uranium from the African nation of Niger. Wilson went to Niger for the CIA to investigate and he found the allegation, which Mr. Bush mentioned in a State of the Union address, to be highly unlikely.
Vice President Dick Cheney and other top administration officials, including White House counsel Alberto Gonzales, also have been questioned in the investigation. A number of news organizations have received federal subpoenas for questioning as well.
Neither the White House nor the Justice Department would offer details about what is believed to be the first time the president has been interviewed by prosecutors investigating possible criminal activity. Officials would not say whether the interview was taped or if Mr. Bush was under oath, nor would they speculate as to why he was questioned.
"I have no idea whether we'll find out who the leaker is," the president told reporters. "Partially because, in all due respect to your profession, you do a very good job of protecting the leakers."
His spokesman said the president considers the leaking of classified
information a very serious matter and said of the questioning he
was "pleased to do his part."