President George W. Bush contended the trailers show that Iraq sought the banned arms, Ari Fleischer said.

"The experts have spoken, and the judgment of the experts is very clear on this matter," Fleischer said.

Bush based his justification for the US-led war on his contention that Iraq possessed such weapons and so threatened US security.

However, the US State Department said its experts had questioned some conclusions of the Central Intelligence Agency.

The experts were "somewhat cautionary in terms of the kinds of the conclusions that they felt could be reached on that particular information at that moment (and) said there were other questions that need to be considered," State Department spokesman Richard Boucher said.

The New York Times had earlier reported on a secret internal document in which the State Department declared it was too early to determine whether the trucks proved anything.

The Central Intelligence Agency had reported to the White House that 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."

Boucher said the State Department experts did not contradict the CIA.

"They did not dispute the conclusions that have been reached by the other agency analysts," he said.

"They pointed out some questions that need to be looked at, issues that needed to be raised," Boucher said.

"We've been assured by the CIA that those issues were considered, were looked at, and that they were confident and remain confident in their judgment that these are mobile biological weapons laboratories."

On May 29, Bush declared that weapons banned by UN resolutions had been found in Iraq.

"We discovered weapons-manufacturing facilities that were condemned by the United Nations," Bush told reporters before leaving for a tour of Europe and the Middle East.

"Biological laboratories described by our secretary of state to the whole world that were not supposed to be there, that are a direct violation of the UN resolutions, have been discovered," he said.

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