But even in this category, the intelligence can be meager, the source said, and often the sites appear on the list more because the CIA wants to learn more about them than because of existing evidence the agency possesses.
Only one tip from U.S. intelligence is known to have produced results. In January, inspectors recovered a cache of documents at the home of an Iraqi nuclear scientist. Although the seizure made headlines, the documents concerned Iraq's long-abandoned efforts on laser enrichment of uranium and did not answer current questions about Iraqi weapons.
Other U.S. officials blamed Blix for failing to publicly announce new evidence that he revealed in his 173-page "working document" of unresolved disarmament issues. Officials were surprised to read that the inspectors recently found an Iraqi drone with a 24 1/2-foot wingspan, which may violate U.N. rules.
According to a copy of the document, inspectors are still trying to determine whether the drone can fly more than 93 miles, the limit set by U.N. regulations. But a senior U.S. official said it "could be used to distribute or disperse" chemical or biological agents and thus was a danger.
"It should have been in [Iraq's weapons] declaration, and it's surprising it was not in Blix's report" to the Security Council on Friday, the official said.
The role of U.S. spying was brought into high relief Feb. 5 when Secretary of State Colin L. Powell presented the council with a dramatic display of U.S. satellite images, bugged conversations, defector accounts and other intelligence to buttress his claims that Iraq is deliberately deceiving the U.N. teams.
But Blix subsequently challenged Powell's interpretation of at least one of the satellite images. And on Friday, Blix said inspectors cannot yet verify claims by "intelligence authorities" that Iraq is shifting illegal weapons by truck to avoid detection, that it is producing and storing weapons in underground bunkers, and that it has built mobile laboratories to produce germ warfare agents.
Inspectors have found "food testing mobile laboratories and mobile workshops ... as well as large containers with seed processing equipment," Blix said. "No evidence of proscribed activities has so far been found."
In response, Powell blamed Baghdad. "If Iraq genuinely wanted to disarm, we would not have to be worrying about setting up means of looking for mobile biological units -- they would be presented to us," he told the council.
"The inspectors should not have to look under every rock, go to every crossroads, peer into every cave for evidence, for proof," he added.
Powell did not repeat a charge he made this week that Iraq is secretly building Al-Samoud 2 missiles while it is destroying others under U.N. auspices.
The charge, which President Bush repeated in his news conference Thursday night, surprised Blix's staff.
An aide said U.S. officials had not provided information that inspectors can use to check -- and presumably stop -- such illegal activities.
*
Drogin reported from the United Nations and Miller from Washington. Times staff writer Robin Wright in New York contributed to this report.
