The New York Times reported that the State Department's intelligence arm had disputed the Central Intelligence Agency's determination that the trailers were mobile biological weapons laboratories, saying it was too early to know.

Asked whether President George W. Bush still believed the CIA and Defense Intelligence Agency's findings, White House spokesman Ari Fleischer replied: "Yes."

"The agencies that are charged with a review of this and have the most expertise on it have rendered their judgment in a very public setting, and it speaks for itself," he said, dismissing the conflicting report.

Bush cited the trailers in a May 29 interview on Polish television, declaring that the United States had "found the weapons of mass destruction" used to justify its invasion.

Citing a secret internal document, the Times said the State Department declared it was too early to determine that the trucks constituted proof of Iraq's suspected biological weapons program.

"It's not uncommon for other agencies that are not as involved to have their say," Fleischer told reporters, shrugging off the State Department's reported findings.

The CIA had made its assertion in a report to the White House, saying the trailers, and a mobile laboratory truck seized near Baghdad in late April, were "the strongest evidence to date that Iraq was hiding a biological warfare program."

US-led forces have yet to report conclusive evidence to support Bush's pre-war contention that Iraq posed an imminent threat to the United States because of weapons of mass destruction and ties to terrorists.

The Bush administration, and its foremost ally, British Prime Minister Tony Blair, have since been accused of embellishing and exaggerating their public case for war.

Separately, Fleischer crowed over a former top Iraqi nuclear scientist's decision to hand over parts of a gas centrifuge and documents to US authorities.

Former Iraqi scientist Mahdi Obeidi said he had buried the material in his Baghdad garden in 1991 on orders from the Saddam Hussein regime, US media reported.

"Dr Obeidi told us that these items, the blueprints and the key centrifuge pieces, represented a template for what would be needed to rebuild a centrifuge uranium enrichment program," said Fleischer.

"He also claimed that this concealment was part of a secret high-level plan to reconstitute the nuclear weapons program once sanctions had ended," the spokesman said.

"These are materials that were deliberately hidden with the purpose being to produce them once the sanctions have been lifted from the country in an effort to reconstitute the nuclear program," said Fleischer.

The United States had insisted that Iraqi scientists with key knowledge of Saddam's alleged weapons programs would never volunteer incriminating information to international inspectors for fear of reprisals.

"We're hopeful that this example will lead to other Iraqi scientists stepping forward to provide information," said Fleischer.

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