WASHINGTON — Secretary of State Colin L. Powell said Friday that he had had assurances from the intelligence community that one of the principal charges he made in a speech to the United Nations last year — that Iraq had mobile weapons laboratories — had been multisourced and was solid at the time.

Mr. Powell urged a presidential commission examining intelligence problems in Iraq to look into what he said was a failure by the Central Intelligence Agency.

Speaking to reporters on a flight home from Europe, Mr. Powell said he had sought to highlight the laboratory charge in his presentation to the United Nations in February 2003 because it was especially "dramatic." But he said he included it only after studying four sources that were used to compile the intelligence.

"I looked at the four elements that they gave me for that one, and they stood behind them," he said of his intelligence briefers. "Now it appears not to be the case that it was that solid."

The remarks were Mr. Powell's broadest acknowledgment yet that his United Nations presentation, which the Bush administration saw as a formal and comprehensive case for the Iraq war, was based at least in part on erroneous information.

"At the time I was preparing the presentation, it was presented to me as being solid," the secretary said.

Mr. Powell has been dogged by questions about his United Nations presentation — which included satellite photos and transcripts of radio intercepts — since the end of the American-led invasion last year. The skepticism toward his case increased this year after David A. Kay, the chief American weapons inspector, said he did not believe that further searching would turn up any unconventional weapons in Iraq.

The inspectors in Iraq concluded that the mobile units had not been used for making weapons and might have had some benign purpose.

Mr. Powell urged the presidential commission to "see whether the intelligence agency had a basis for the confidence that they placed in the intelligence at the time." The commission, which is headed by Laurence H. Silberman, a federal judge, and former Senator Charles S. Robb of Virginia, will not present its findings until next spring.

"If the sources fall apart, we need to find out how we got ourselves into that position," Mr. Powell said, "and I've had discussions with the C.I.A. about that."

© Copyright 2004 The New York Times Company

###