Agency Details Iran’s Ambitious Pursuit of Advanced Centrifuges

International inspectors have found new evidence that Iran engaged in a more ambitious program than it had admitted to develop advanced machines for producing material that could be used in nuclear weapons, according to a report obtained Tuesday.

Discoveries by the International Atomic Energy Agency, the United Nations’ nuclear watchdog, contradicted previous claims by Iran that its scientists had made little attempt to manufacture sophisticated Pakistani-designed P2 centrifuges.

IAEA inspectors also found traces of weapons-grade uranium that indicated Iran either had imported nuclear-related components from a country other than Pakistan or has made more progress than previously known in developing its own ability to produce material capable of being used in nuclear weapons.

The latest in a yearlong series of reports by the IAEA criticizing Iran’s nuclear program said serious questions remained about the scope and intentions of Tehran’s atomic activities, but it did not say evidence of a weapons program had been found.

Still, the findings seemed to ensure that pressure on Iran will not be eased later this month when the agency’s board meets in Vienna. The report was prepared for the June 14 board meeting and a copy was provided to The Times by a Western diplomat.

Washington has argued that Tehran is pursuing a nuclear weapons program behind the facade of a civilian effort. Iranian officials have consistently said that the program is purely to generate electricity.

At a meeting of legislators from North Atlantic Treaty Organization countries in Bratislava, Slovakia, IAEA Director-General Mohamed ElBaradei said it was not clear whether Iran’s program was for peaceful purposes or had a military dimension.

“We haven’t seen concrete proof of a military program, so it’s premature to make a judgment on that,” he said, according to Reuters news agency.

The report was worded carefully to try to keep negotiations open with Tehran. The IAEA praised Tehran’s cooperation but said Iran continues to change its story on key issues and withhold information.

Jon B. Wolfsthal, a nonproliferation expert at the Carnegie Endowment for International Peace in Washington, said after reviewing the report that it did not answer the question of Tehran’s ultimate nuclear intentions.

“It’s clear from this report that we have not gotten a clear picture of Iran’s program,” Wolfsthal said. “There are still major gaps.”

The IAEA report focused a particularly harsh light on Iran’s efforts to develop the sophisticated P2 centrifuges from designs and components purchased from the black market network run by Pakistani scientist Abdul Qadeer Khan.

“Important information about the P2 centrifuge program has frequently required repeated requests, and in some cases continues to involve changing or contradictory information,” the report said.

Iran acknowledged last year that it had developed an earlier Pakistani-based centrifuge, the P1. Centrifuges are hollow cylindrical devices that enrich uranium for use in nuclear reactors or weapons. After IAEA inspectors discovered plans for the P2 last fall at a nuclear facility, Tehran acknowledged that it also had an interest in the advanced version, which is faster and more efficient.

Iran said it had inadvertently left the P2 plans out of its disclosures to the IAEA because they constituted such a small program. It said it had bought the designs in 1995 but had conducted only minor research on the machines in 2001.

In addition, Iranian officials told the IAEA that only a few P2 components had been manufactured at a private company in Iran and that nothing had been purchased abroad.

But the IAEA report contradicts those claims. Iran bought components for the P2 on the black market and other parts were manufactured at a military workshop previously off-limits to inspectors, not at the private company, said the report.

The report also said a private contractor working for the Iranian government tried to buy 4,000 magnets for P2 centrifuges and had suggested that Iran might want many more in future.

“They dangled the prospect of buying tens of thousands of magnets,” a Western diplomat said in a telephone interview from Vienna. “With two magnets per centrifuge, this looks like more than a small-scale research project.”

The IAEA also is investigating the origins of traces of uranium suitable for use in weapons that were discovered at three facilities in Iran in recent months, including one previously undisclosed location.

Inspectors first found traces of weapons-grade uranium on centrifuge parts last year at the Natanz pilot plant and Kalaye Electric Co. Iranian officials said the components must have been contaminated when they were purchased on the black market.

The IAEA later determined that the components came from Pakistan and that the contamination appeared to match uranium enriched at Pakistani plants.

But more recently, inspectors found uranium enriched to 36%, a level suitable for bombs, at Kalaye and a third site identified only as Farayand Technique.

The IAEA report said the second batch of traces did not appear to come from Pakistan. “It is unlikely ... that the agency will be able to conclude that the 36% ... contamination was due to components originating from the state in question,” it said.

The Western diplomat said one possibility was that the second batch of traces came from components purchased from Russia.