Russia cast doubt today on Iran's claims that it is now producing enriched uranium on "an industrial scale", saying that it had seen no evidence of a recent breakthrough in the Iranian nuclear programme.

Reacting to claims made yesterday by Mahmoud Ahmadinejad, the Iranian President, and the country's nuclear technicians, the Russian Foreign Ministry joined France and Australia in expressing scepticism about Tehran's capabilities.

“We are not aware of any technological breakthroughs in the Iranian nuclear programme recently which would change the nature of work on enrichment being carried out in the country,” the Russian Foreign Ministry said in a statement.

The Foreign Minister, Sergei Lavrov, then said that he was awaiting a response from the International Atomic Energy Agency before believing that Iran had taken a significant step in its nuclear programme. Two IAEA inspectors arrived in Tehran today on a scheduled visit and their report is expected to shed light on how much progress Iran has made.

“We haven’t got a confirmation yet that they have actually begun uranium enrichment at the new cascades," said Mr Lavrov.

The note of cautious disbelief was struck on the second day of condemnations levelled at Tehran, which has openly defied the UN's demand that it stop enriching uranium and yesterday raised the rhetorical stakes by claiming to be about to inject uranium gas into 3,000 centrifuges at its main enrichment plant at Natanz.

Atomic experts say that 3,000 centrifuges running continuously would produce enough enriched material for a nuclear bomb within a year, although Iran has so far only managed to run 164 experimental centrifuges successfully, often with just 20 per cent turning at one time. Diplomats reported last week that Iran had installed 1,000 centrifuges but had not yet injected them with gas.

Russia, which joined the UN Security Council's second resolution demanding the suspension of Iran's nuclear programme in February, is considered a key player in attempts to bring about a negotiated solution to the confrontation. Moscow has assisted Tehran with the building of its first nuclear power plant at Bushehr, although that project has been delayed by Iran's failure to keep up with payments for Russian parts.

Despite the doubts — the Australian Foreign Minister, Alexander Downer, said today he was not sure if the Iranian statement "is true or not" — the EU said this afternoon that it regarded Tehran's announcement, made with great fanfare yesterday, with concern. The UN has demanded that Iran stops enriching uranium as a precondition for talks.

"The presidency of the European Union views Iran’s announcement that it wants to enrich uranium on an industrial scale with great concern,” said the German Foreign Ministry on behalf of the bloc today.

“The presidency of the European Union renews its urgent call that Iran meet the demands of the international community so that a return to the negotiating table and a solution to the conflict over the Iranian nuclear programme is possible.”

Iran meanwhile, flushed with what it regards as the successful conclusion to its seizure of 15 British military personnel in the Gulf last week, continued to talk up the advance in its nuclear programme, saying it was time for the world to recognise the "new realities" of its atomic project.

“Our situation before enriching uranium was different. It changed at the stage of pilot, and then at the industrial stage, which we have obtained," Mohammad Saeedi, the deputy head of Iran’s Atomic Energy Organisation, told the ISNA news agency. "We have a superior position."

“We have passed the stage of setting conditions for talks," he said. "We believe that other parties should move forward based on new realities.”

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