Iran asked the International Atomic Energy Agency ``to remove the seals as it wants to start work at the uranium conversion facility in Isfahan,'' a diplomat close to the IAEA said, though the agency was not acting immediately.

A second diplomat said ``the clock will depend on the IAEA'' and that the agency ``may be looking for formulas to delay so that cooler heads might prevail'' because a resumption by Iran of uranium ore conversion is certain to set off an international crisis, with the United States charging that Iran is secretly developing nuclear weapons.

Uranium ore conversion is a precursor to uranium enrichment, which makes uranium fuel for civilian nuclear power plants but what can also be the explosive core of atom bombs.

Officials in Teheran said Monday that Iran was set to resume conversion work, ending a nine-month suspension agreed with the European Union and verified by the IAEA as the two sides try to work out guarantees that Iran's nuclear program is peaceful.

EU negotiators Britain, France and Germany have warned Iran that any resumption of either conversion or enrichment will prompt them to back US-led calls for Teheran's nuclear program to be referred to the UN Security Council for possible sanctions.

The EU would first have to call an emergency meeting of the IAEA's 35-nation board of governors in Vienna, which would then send the Iranian dossier to the UN.

Germany urged Iran Monday not to take any ``unilateral steps'' that could endanger negotiations.

Iranian negotiator Agha Mohammadi said in Teheran that an IAEA inspection team in Iran would witness the removal of the seals placed on the plant by the UN nuclear watchdog once the letter had been handed over.

Both conversion and enrichment activity were suspended by Iran in November for the duration of talks with the EU on providing guarantees that it is not working on nuclear weapons.

Mohammadi said the decision to resume conversion had been taken after EU foreign policy chief Javier Solana failed to provide ``guarantees'' that a detailed package to be put forward by Britain, France and Germany in the coming days would recognize Iran's right under the nuclear Non-Proliferation Treaty to carry out nuclear fuel cycle work.

Iran regarded his failure to do so by the time the deadline expired as a breach of November's agreement and immediately took the final decision to resume conversion.

Mohammadi insisted Iran did not want to end the talks process begun with the EU.

``We're going to continue negotiations,'' he said. ``We're not going to resume enrichment.''