WASHINGTON - The Iranian government, confronted with new evidence obtained from the secret network of nuclear suppliers surrounding Abdul Qadeer Khan, has acknowledged that it possesses a design for a far more advanced high-speed centrifuge to enrich uranium than it previously revealed to the International Atomic Energy Agency.
The centrifuge, called a Pak-2 because it marked Pakistan's second-generation design, would allow Iran to produce nuclear fuel far more quickly than the equipment that it reluctantly revealed to the IAEA last year. But it is unclear whether Iran succeeded in building the new equipment, which is the type that the Khan network sold to Libya in recent years.
Some details of Iran's shift were reported in yesterday's editions of the Financial Times. Iran's new statements to the IAEA, which compelled the country last year to open to fuller inspections, are important for two reasons. They mark the first evidence that Iran did not tell the full truth when it turned over to the IAEA documents that it said described all the important elements of its program to enrich uranium. The enrichment program, Iran admitted at the time, had been conducted in secret and out of the view of international inspectors for 18 years.
The revelation has also touched off a debate within the American and European intelligence communities over whether the Khan network also sold a full weapon design to Iran, similar to the one found in Libya.
"It's natural to question whether the Iranians got everything the Libyans did," one senior administration official said. "Why wouldn't they?"
But yesterday in Rome, Iran's foreign minister, Kamal Kharrazi, denied that the country is pursuing a nuclear weapon and said that the uranium enrichment is intended solely for fueling nuclear power plants.
"Basically, we do not think that a nuclear weapon is going to bring us more security," Kharrazi said. "It is not part of our doctrine."
He added later that "we do not have anything to hide and we are ready to be inspected more seriously by IAEA inspectors."
According to diplomats in Vienna, Austria, the IAEA compiled a stack of evidence suggesting that Iran already had more sophisticated uranium enrichment designs than it had admitted.
"Partly the evidence came from Libya, and partly from the network of suppliers and from member states" of the inspection agency, one senior European diplomat said.
Another official said the agency had privately charged Tehran with hiding that fact from the inspectors. The Iranians strongly denied any effort to deceive, the official said, and some Western experts familiar with the debate and the evidence said Iran's stance had some merit.
"The truth is somewhere in the middle," one official said, adding that the degree to which Iran disclosed details of its technology last year was at the heart of the dispute.
The diplomat added that the Iranians had actually tried to build some prototype P-2 centrifuges but found the steel-rotor devices so difficult to manufacture that they opted instead for the easier P-1 variety, which uses aluminum rotors spinning about half as fast.
He added that Tehran, if it decided in the future to try manufacturing the more advanced centrifuges, could probably not do so itself but would have to rely heavily on imported steel parts.
Given the new disclosures about the Iranian plans and work on advanced centrifuges, he said, the next logical question for the IAEA is whether Iran, like Libya, also got from the Pakistani black market plans for an atom bomb.
"They're asking that," he said. But American officials say that so far, they have received no convincing answers.
In recent days, the Bush administration has taken an increasingly hard line against Iran, openly questioning why it is continuing to build parts for its centrifuges. (Iran responds that it is simply fulfilling previously signed contracts for domestically produced equipment.)
President Bush, speaking Wednesday at the National Defense University, said that "the government of Iran is unwilling to abandon a uranium enrichment program capable of producing material for nuclear weapons."
He proposed rules in that speech that would effectively outlaw any effort by Iran or states like it to produce nuclear fuel of any kind.