WASHINGTON – The White House tried today to quell the furor over the leaking of sensitive prewar intelligence on Iraq, as President Bush’s spokesman insisted that the president had the authority to declassify and release information “in the public interest” and had never done so for political reasons.

Scott McClellan, President Bush’s spokesman, insisted that any release of information was “in the public interest.”

The spokesman, Scott McClellan, said a decision was made to declassify and release some information to rebut “irresponsible and unfounded accusations” that the administration had manipulated or misused prewar intelligence to buttress its case for war.

“That was flat-out false,” Mr. McClellan said.

Mr. McClellan was barraged at a news briefing by questions over assertions by I. Lewis Libby Jr., the former chief of staff to Vice President Dick Cheney, that President Bush authorized him, through Mr. Cheney, in July 2003 to disclose key parts of what was until then a classified prewar evaluation, or National Intelligence Estimate, on Iraq.

At the time, the Pentagon had hardly finished basking in the easy military victory when it was caught up in questions over the failure to find deadly unconventional weapons in Iraq – the main rationale for going to war.

One of the findings in the prewar intelligence data was that Saddam Hussein was probably seeking fuel for nuclear reactors.

Mr. McClellan said the Democrats who pounced on Mr. Libby’s assertions that Mr. Bush had given him, through the vice president, the authority to talk to a reporter about some material in the intelligence estimate were “engaging in crass politics” in refusing to recognize the distinction between legitimate disclosure of sensitive information in the public interest and the irresponsible leaking of intelligence for political reasons.

Mr. Libby told a grand jury he discussed the intelligence estimate with Judith Miller, then with The New York Times, on July 8, 2003. Ten days later, the intelligence estimate was formally declassified, a move that Mr. McClellan said again and again was in the public interest and not politically motivated. Mr. McClellan deflected questions on what role, if any, Mr. Bush had in setting the parameters of Mr. Libby’s discussion with Ms. Miller.

Meanwhile, Democrats continued to assail the administration.

“This is a serious allegation with national security consequences,” Senator Harry Reid of Nevada, the minority leader, said today on the Senate floor. “It directly contradicts previous statements made by President Bush, it continues a pattern of misleading by this Bush White House, and it raises somber and troubling questions about the Bush administration’s candor with the Congress and the public.”

Mr. Reid said it was time for the president to say whether, in fact, he authorized the disclosure of the prewar intelligence, as Mr. Libby said he had. “He must tell the American people whether the Bush Oval Office is the place where the buck stops, or the leaks start,” Mr. Reid said.

Mr. McClellan was in the somewhat odd position of not disputing that President Bush was involved in the disclosure of hitherto classified information, while describing any such disclosure as being in the public good.

Mr. McClellan, who noted that a president has the authority to declassify intelligence, said today that he was “not getting into confirming or denying things, because I’m not commenting at all on matters relating to an ongoing legal proceeding.”

He was alluding to the trial of Mr. Libby, the vice president’s former chief of staff, on charges that Mr. Libby committed perjury and engaged in obstruction of justice in connection with an inquiry over who unmasked Valerie Wilson, an undercover officer for the Central Intelligence Agency, in the summer of 2003.

The unmasking occurred shortly after Ms. Wilson’s husband, the former diplomat Joseph Wilson, wrote in The New York Times that he doubted reports that Iraq was trying to obtain uranium from Niger.

Some Democrats accused the White House at the time of destroying Ms. Wilson’s cover to retaliate against her husband, but the White House repeatedly denied the accusations.

Mr. McClellan was asked today whether the president’s own words at the time (“If there’s a leak out of this administration, I want to know who it is”) and Mr. Libby’s recent assertion, contained in a court filing, demonstrated inconsistency, at best.

Not at all, Mr. McClellan said. “Declassifying information and providing it to the public when it is in the public interest is one thing,” he said. “But leaking classified information that could compromise our national security is something that is very serious. And there is a distinction” – a distinction Democrats refuse to see, he said repeatedly.