Europe Warns Iran

"The Presidency of the European Union has noted with great concern the announcement by Iran that it intends to begin uranium enrichment on an industrial scale," Germany, the current EU president, said a statement on Tuesday.

"The presidency of the EU once again urges Iran to comply with the demands of the international community and to create the conditions for a return to the negotiating table and for a solution to the conflict surrounding the Iranian nuclear program."

Iranian President Mahmoud Ahmadinejad announced on Monday that the country had set up an "industrial scale" operation to enrich uranium.

Enrichment remains sticking point

Experts said this would mean operating around 3,000 centrifuges to produce enriched uranium -- nearly 10 times the number Iran had previously declared.

Uranium enrichment is the key sticking point in the row between Iran and the West because the process can also make the fissile core for an atomic bomb. The western powers accuse Tehran of seeking to make nuclear arms while Tehran insists it is for power generation only.

Russia's took a more restrained line. A foreign ministry said Tuesday that for the moment it saw no evidence that Iran had made the breakthrough it claims in its nuclear fuel enrichment program.

"We do not know of any recent technological breakthroughs in the Iranian nuclear program that would change the character of the work in the field of enrichment," ministry spokesman Mikhail Kamynin said.

Stiff response from West

But French Foreign Minister Philippe Douste-Blazy called Iran's announcement "a bad sign."

"I once again urge Iran to respect Security Council resolutions, which demand the suspension of all sensitive nuclear activities," he added.

Britain and the United States also issued robust responses.

The United States on Monday said making good on Ahmadinejad's claim would expose Iran to tougher international pressure.

US State Department spokesman Sean McCormack said Iran was "almost completely encircled by the international community because of their actions, and that pressure is only going to increase if they persist."

A British Foreign Office spokesman said Monday that Iran's latest declaration was a further breach of IAEA and UN resolutions.

Doubts over Iran's abilities remain

Iran defiance of Western calls to suspend enrichment have earned it two sets of UN sanctions since December.

One US-based analyst also expressed doubt as to whether Iran has begun to enrich uranium with their larger array of centrifuges.

"The purpose today was to publicly state that they had the centrifuges," said David Albright, a former UN nuclear inspector and now president of the Washington-based Institute for Science and International Security.

"It would be a big surprise though if they did start to enrich," he said, adding that putting the centrifuges into action would "seriously reduce their chances of having any meaningful negotiations with the Europeans."

Talks between the European Union's foreign policy chief, Javier Solana, and Iran's chief nuclear negotiator, Ali Larijani, are expected to resume soon, though dates have not been announced.

Solana's office said on Tuesday that there was no way to verify Iran's claims unless international inspections were resumed.