Mr. Bolton said the United States has no doubt Iran is continuing to pursue a nuclear weapons program. He was responding to reports from Western diplomats at the headquarters of the International Atomic Energy Agency in Vienna who say the agency's inspectors in Iran have found plans for a sophisticated centrifuge, which can be used to enrich uranium for nuclear weapons.

"The information that the IAEA has learned is certainly consistent with information that we had, and it's not surprising," he said. "It's another act of Iranian deception and not something that leads to any feeling of security that they're carrying through on their commitments to suspend enrichment activity. We'll be looking at it seriously and we'll consult with the German government, and the British and the French, to try and decide what to do next."

Mr. Bolton said what the IAEA inspectors found is clearly a violation of the commitment Iran made last year to stop enriching uranium.

The United States has long maintained that Iran is secretly developing nuclear weapons.

Iran denies the charge, and its foreign minister Kamal Kharrazi said in Rome Thursday all Iran's nuclear technology is used for peaceful purposes. "We do not think nuclear weapons are going to bring us more security," he said. "That is why we have signed the additional protocol, because we have nothing to hide."

Mr. Kharrazi welcomed the IAEA inspectors, but he disagreed with their reported findings about the centrifuges that could be used to make weapons grade nuclear material.

If the report is confirmed, the IAEA board could refer the matter to the U.N. Security Council.