National security adviser Condoleezza Rice said Sunday she knew of a debate within the US government about the purpose of aluminum tubes found in Iraq, which she and other officials had brandished before the war as proof of Saddam Hussein's nuclear ambitions.

In a series of television interviews Sunday, Rice insisted however that she only later learned that the Energy Department believed the aluminum tubes were actually meant for conventional weapons, denying a report in The New York Times that she knew of those concerns before using the tubes to argue for war.

"At that time we understood there were some debates within the intelligence community. I later learned that the Energy Department believed that these tubes might be for something else," she told NBC television's "Today Show."

Speaking on the campaign trail in the town of Austintown, Ohio Sunday, Democratic presidential hopeful John Kerry said Times report is a stinging indictment of the Bush administration's prewar intelligence and foreign policy judgment.

"There are very serious questions about whether the administration was open and honest in making the case for war in Iraq," Kerry said on a campaign sweep taking him through several rust-belt communities.

"These are questions that the president must face. These are question that the president has to answer fully to the American people and the troops," he said.

Kerry's campaign spokesman Joe Lockhart expanded on those concerns

"Secretary (of State Colin) Powell went up and based most of his assessment on Saddam's nuclear threat on these aluminum tubes to the United Nations," he said.

"Condoleezza Rice raised the specter of a mushroom cloud ... Vice President Cheney ... didn't say there was debate. He said this was a fact."

"This is about what the president knew, what he withheld from the American public, if anything," Lockhartt said. "These are questions he should answer now."

Democratic Senator Bob Graham accused the White House of deliberately using information it knew to be false to bolster the case for invading Iraq.

"It is an outrage of tremendous proportions, and is not only a statement of the intelligence of this administration, but the fundamental character of this administration that they would so mislead the citizens of the United States and the world," Graham told reporters.

The report is another blow to White House credibility on foreign policy matter as the presidential campaign enters a critical 10-day period, with a vice-presidential faceoff on Tuesday and two more scheduled debates between Bush and Kerry.

Kerry's strong performance in Thursday's debate with Bush on international affairs, combined with weekend polls showing Kerry with a slim advantage over Bush after trailing him for months, have reinvigorated the Democrat's bid for office.

On Tuesday Kerry's running mate, North Carolina Senator John Edwards, faces Vice President Dick Cheney in a 90-minute debate on the campus of Case Western Reserve University in midwestern city of Cleveland, Ohio.

The charismatic Edwards, a former trial lawyer, will sit across a table from Cheney, a serious, often dour conservative with a quick wit and sharp tongue. A television journalist will moderate the event.

Kerry and Bush in the meantime are preparing for two more debates: the rivals meet Friday in the midwestern city of St. Louis, Missouri in a town hall format to discuss all topics, and on October 13 at Arizona State University in Tempe, Arizona to discuss domestic and economic issues.

Speaking on CBS television on Sunday, White House communications director Dan Bartlett emphasized that Kerry "has been somebody who has debated all his life and is a good debater. But there's a difference between having style and having rhetorical points."

He then dismissed the Democrat as "a walking contradiction when it comes to the issue of Iraq." Kerry voted in favor of authorizing Bush to go to war, then opposing the way the war is being waged.

Lockhart, a former spokesman for president Bill Clinton and now a senior Kerry adviser, said on CBS that Bush's mistake was expecting to debate a caricature that "100 million dollars in negative advertising had created."

But Bush "didn't know how to handle" the real John Kerry. "It was a guy who was clear, who was consistent, and the president didn't have an answer."

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