The White House, meanwhile, charged there was no doubt that Iran seeks such weapons, rebuffing the head of the UN watchdog.

The technical talks in Tehran are being held under an agreement between the two sides which Iran hopes will prevent further UN Security Council resolutions but which has been criticised by Washington for not going far enough.

The deputy director general of the International Atomic Energy Agency (IAEA), Olli Heinonen, arrived in Tehran earlier on Monday and in the afternoon went into talks with leading national security official Javad Vaeedi.

Heinonen will have three days of discussions on Iran's use of uranium-enriching P1 centrifuges and its research into the more sophisticated P2 versions as part of the agreement.

"So far we have done many things but there remains a lot of other work that hopefully will be done," Heinonen said on arrival, according to state-run news agency IRNA.

The talks are part of a deal Heinonen clinched in August for Iran to answer outstanding questions over its atomic programme so the agency can conclude a four-year investigation into its nature.

Based on the result of these talks, IAEA chief Mohamed ElBaradei is due to submit a report on the status of the Iranian uranium enrichment programme by the end of November.

ElBaradei, who has repeatedly defended the accord in the face of US criticism, said on Sunday there was still no evidence to back the US claims Tehran was seeking a nuclear bomb.

"I have not received any information that there is a concrete active nuclear weapons programme going on right now," he told CNN.

But the White House countered that the Islamic republic was "enriching and reprocessing uranium and the reason that one does that is to lead towards a nuclear weapon".

And French Defence Minister Herve Morin, whose country has strongly backed the United States in recent months, also dismissed ElBaradei's comments, saying his information "gives us the opposite feeling."

Mohammad Saeedi, the deputy head of Iran's atomic energy organisation, on Monday pledged to cooperate with the UN nuclear watchdog to clear up any remaining issues before the report comes out.

"It is possible that the agency raises new questions and points, before ElBaradei's report, under the framework of the same (previous) questions," said Saeedi, who greeted Heinonen at Tehran airport.

"In this case, we will provide the necessary answers."

Saeedi said that the talks on P1 and P2 centrifuges, through "explicit and open discussions," were close to reaching a conclusion.

The centrifuge talks focus on the key sticking point between Iran and the West -- Iran's right to uranium enrichment, a process that makes nuclear fuel but can also be developed to create the core of an atomic bomb.

Iran's leaders have repeatedly said they will never suspend enrichment, in flagrant defiance of repeated Security Council resolutions calling on Tehran to suspend the process.

Israeli Foreign Minister Tzipi Livni, on a three-day visit to Beijing, warned of "the grave implications that a nuclear Iran will have on the stability of the planet."

The White House has recently ramped up its rhetoric against Iran, warning the world about "nuclear holocaust" and "World War III" if Tehran gets atomic weapons.

Meanwhile, a top general in Iran's Revolutionary Guards, Brigadier General Ali Fahdavi, warned that his forces were ready "if necessary" to carry out suicide operations in the Gulf.

Washington accuses Tehran of seeking nuclear weapons and has never ruled out the option of military action to end its defiance. Iran, however, insists it wants only to generate electricity for a growing population.

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.