It would be a second round after Iran already processed 37 tonnes of ore and diplomats said the amount of uranium hexafluoride (UF6) gas the Iranians would have after processing the 50 tonnes would be enough to make highly enriched uranium for up to 10 atomic bombs.

The diplomats also said reports that the UF6 is too contaminated to be put into the centrifuges that make enriched uranium were wrong.

Iran is currently suspending enrichment work but "the current batch is good enough for a crash nuclear weapons program, if Iran doesn't mind ruining a lot of centrifuges along the way," a Western diplomat said.

Mark Fitzpatrick, a non-proliferation expert at London's International Institute for Strategic Studies (IISS) think tank, told AFP: "My understanding is that the product can be used to enrich uranium, although it will corrode centrifuge machines over time."

Fitzpatrick added: "But many of the centrifuge machines will crash upon start-up anyway, so contamination may be the least of Iran's worries."

A non-Western diplomat said: "Fifty tonnes is considered to be a very large quantity and the feeding of such a quantity in the system clearly indicates that Iran believes in its capability to produce UF6 of good quality in the conversion process."

A diplomat said the Iranians have told the IAEA "they intend to resume full conversion work on November 26," which would be after an IAEA board meeting November 24-25 that will consider sending the Islamic Republic to the UN Security Council over its nuclear fuel work.

IAEA officials refused to comment on a specific date.

Iran is defying the international community by pushing ahead with uranium conversion.

Talks with the European Union on guaranteeing Iran is not secretly developing nuclear weapons collapsed in August when Iran broke a suspension of conversion it had begun nine months earlier as a confidence-building measure.

The IAEA then in September passed a resolution calling on Iran to cease all nuclear fuel work, including conversion, and to cooperate fully in an IAEA investigation into its atomic program.

All rights reserved. � 2005 Agence France-Presse. Sections of the information displayed on this page (dispatches, photographs, logos) are protected by intellectual property rights owned by Agence France-Presse. As a consequence, you may not copy, reproduce, modify, transmit, publish, display or in any way commercially exploit any of the content of this section without the prior written consent of Agence France-Presse.