The White House faced new questions Wednesday about President Bush's contention three years ago that weapons of mass destruction had been found in Iraq.

The Washington Post reported that a Pentagon-sponsored team of experts determined in May 2003 that two small trailers were not used to make biological weapons. Yet two days after the team sent its findings to Washington in a classified report, Bush declared just the opposite.

"We have found the weapons of mass destruction," Bush said in an interview with a Polish TV station. "We found biological laboratories."

Bush spokesman Scott McClellan said Wednesday that Bush was relying on information from the Central Intelligence Agency and the Defense Intelligence Agency when he said the trailers seized after the 2003 invasion were mobile biological laboratories. That information was later discredited by the Iraq Survey Group in its 2004 report.

The CIA and DIA publicly issued an assessment one day after the Pentagon team's report arrived in Washington that said U.S. officials were confident that the trailers were used to produce biological weapons. The assessment said the mobile facilities represented "the strongest evidence to date that Iraq was hiding a biological warfare program."

McClellan said it was unclear whether officials at the White House were aware of the contradictory field report when Bush repeated the claim in the television interview.

"If and when the White House became aware of this particular issue, I'm looking into that matter," McClellan said. "The White House has asked the CIA and the DIA to go and look into that issue."

The Post did not say that Bush knew what he was saying was false. But ABC News did during a report on "Good Morning America," and McClellan demanded an apology and an on-air retraction. ABC News said later in a clarification on its Web site that Charles Gibson had erred. McClellan said he had received an apology.

"This is nothing more than rehashing an old issue that was resolved long ago," McClellan said. "I cannot count how many times the president has said the intelligence was wrong."

"The intelligence community makes the assessment," he said. "The White House is not the intelligence-gathering agency."

Navy Cmdr. Greg Hicks, a Pentagon spokesman, said in a written statement that the report from the expert team was sent to the DIA on May 27, 2003, but he said the findings were not vetted until over the summer. The statement did not say whether the information was immediately shared with the White House.

"This further analysis led to the conclusion of the ISG that the mobile units were impractical for biological agent production and almost certainly designed and built for the generation of hydrogen," Hicks' statement said.

CIA spokeswoman Jennifer Dyck declined to speak specifically about the classified field report but said in general that producing a finished intelligence report takes time, coordination, debate and vetting.

"This is not a fast process, especially when dealing with complex issues," she said. "It is not typically something that happens in a matter of hours."

The trailers ¡ª along with aluminum tubes acquired by Iraq for what was believed to be a nuclear weapons program ¡ª were primary pieces of evidence offered by the Bush administration before the war to support its contention that Iraq was making weapons of mass destruction.

Intelligence officials and the White House have repeatedly denied claims that intelligence was exaggerated or manipulated in the months before the U.S.-led invasion of Iraq in March 2003. The Iraq Survey Group concluded in 2004 that there was no evidence that Iraq produced weapons of mass destruction after 1991.