Iran Resumes Uranium Enrichment Work

PARIS, June 8(NYT) — Iran restarted important nuclear activities on the same day this week that six world powers offered it incentives aimed at encouraging the complete suspension of the nuclear work, the International Atomic Energy Agency reported on Thursday.

On Tuesday, Iran restarted the pouring of a raw form of uranium into a set of 164 centrifuge machines to produce enriched uranium, said the I.A.E.A., the nuclear monitoring agency based in Vienna.

That same day, Javier Solana, the European Union's foreign policy chief, was in Tehran, where he presented Iranian leaders with an international package of incentives to help resolve the crisis caused by the country's nuclear program.

There was no explanation for Iran's decision. But it seemed to underscore its often stated determination not to be bullied into accepting any deal requiring it to end activities related to uranium enrichment.

The decision also could be intended to win more concessions from the United States, Russia, China, France, Britain and Germany, which proposed the incentives package.

The revelation is likely to stiffen the resolve of the United States and the Europeans in particular that a complete freeze of uranium enrichment and reprocessing activities is a condition for formal negotiations.

In April, Iran succeeded in enriching uranium to the low levels needed to fuel a nuclear reactor. Later that month, without explanation, it stopped introducing the raw form of uranium into the fast-spinning centrifuge machines that concentrate uranium into material that can fuel nuclear reactors or bombs. The empty machines continued to run, which is necessary to prevent them from wobbling and crashing.

Iran has continued to enrich uranium in two test centrifuges, so there was never a total halt, the agency report said, and Iran is continuing to build two more 164-centrifuge networks as part of its long-term plan to enrich more uranium.

The report also said that the agency's inspectors had found new traces of highly enriched uranium on equipment in Iran. But the agency has not yet determined whether the traces came from equipment Iran had bought from an outside source or from its own enrichment.

The report also found fault with Iran for failing to make progress on a number of longstanding issues of concern about Iran's nuclear program that have eroded the I.A.E.A.'s confidence in the country.

The report was sent to the 35 countries on the I.A.E.A.'s decision-making board in advance of its regularly scheduled meetings in Vienna next week. It was distributed on a confidential basis but was quickly made available to reporters.

Reports of the apparent slowdown of the uranium enrichment had caused speculation that Iran — or at least part of its leadership — might be trying to send a positive signal to the world and to find a face-saving way out of its nuclear quandary.

Another explanation for the slowdown had been that Iran was having difficulties mastering the process of producing nuclear fuel in the centrifuges. The decision to restart enrichment could be an effort to show that it was not having such problems.

Mr. Solana, apparently unaware of the critical I.A.E.A. report, was upbeat in remarks to reporters in Paris on Thursday. "I am more optimistic than pessimistic," he said after emerging from a meeting about the Iran crisis with President Jacques Chirac of France. Calling the incentives package "a pretty, beautiful package," he said it provided a way for the Iranians to extricate themselves from the crisis over their nuclear program.

"What is needed is to work with them with respect," Mr. Solana said, adding that the countries that made the offer had "the intention to work with them in the most constructive fashion possible."

Mr. Solana, who has emerged as the interlocutor for the six world powers with Iran, also said that "weeks, the coming days, will be enough for a first response" from Iran. He has expressed willingness to engage in pre-negotiation with Iran and even to return there if more clarification is needed. Whether Iran's new production of nuclear fuel would affect the strategy was not known.

In Washington, the State Department spokesman, Sean McCormack, said the United States was still hopeful that Iran would respond positively to the incentives package, but declined to comment in the report that Iran had moved into a new phase of uranium enrichment.

In his first public comments since Iran was presented with the incentives package, President Mahmoud Ahmadinejad said on Thursday that Iran was willing to restart negotiations to resolve misunderstandings, but would never give up its "rights," code for what Iran has consistently said is its sovereign right to enrich uranium for peaceful purposes under the Nuclear Non-Proliferation Treaty.

"On behalf of the Iranian nation, I'm announcing that the Iranian nation will never hold negotiations about its inalienable rights with anybody, but we are for talks about mutual concerns to resolve misunderstandings in the international arena," he told a crowd of thousands in the city of Qazvin.

He stopped short of categorically stating that Iran would not suspend uranium enrichment, as the six nations demand it do before negotiations begin on the incentives.

"If they think they can threaten and hold a stick over Iran's head and offer negotiations at the same time, they should know the Iranian nation will definitely reject such an atmosphere," he said.

As the incentives proposal was being drafted last month, Mr. Ahmadinejad said that accepting it would be like exchanging "candies for gold."