New York/Vienna  - UN Security Council members on Friday said a new UN report offered proof that Iran is seeking nuclear weapons, while some raised the spectre of Iran being able to produce an atomic bomb with the amount of enriched uranium it has.

The International Atomic Energy Agency (IAEA) in Vienna said in an updated report late Thursday that the Tehran regime has underreported by a third the extent of its enrichment activities.

The IAEA said Iran has produced 1,110 kilogrammes of low-enriched uranium. Non-proliferation experts estimate that 1,000 to 1,700 kilogrammes are theoretically needed for use in an atomic weapon, although the material would have to be further enriched.

British Ambassador John Sawers said the report showed that Iran was making advances in mastering its capability to enrich uranium for military use.

"What we do have is proof that it is not for civilian purposes because Iran has only one civilian nuclear power station run with nuclear fuel provided by Russia," Sawers said. "So what is the purpose of producing enriched uranium if not to stock it for other purposes?"

Envoys from Japan and France said the 15-nation council is concerned by the new findings and would have to tackle the new situation with Iran.

"They are going on with the programme and not complying anymore with the IAEA's rules," French Ambassador Jean Maurice Ripert said at UN headquarters in New York. "We will have to deal with it."

In three rounds of sanctions, the Security Council has demanded that Iran end its uranium enrichment programme, end the construction of a heavy-water reactor and allow IAEA inspectors in there.

In Vienna, diplomats close to the IAEA, the UN's nuclear watchdog, said that the finding has been blown out of proportion. They pointed out that the low enriched uranium that Iran has would have to be refined even more.

"This is theoretical and this is dependent on several variables. They would have to throw out the inspectors and leave the NPT (Nuclear Non-Proliferation Treaty)," one senior diplomat told Deutsche Presse-Agentur dpa.

"In my view, it was quite hyped in the media," another diplomat said.

The United States said the IAEA's report reinforced doubts that Iran's intentions are purely peaceful, and that time was of the essence in forcing Iran to abandon its nuclear ambitions.

But the White House would not comment specifically on the allegations that Iran had enough fissile material to produce a nuclear bomb.

"This White House understands that, working with our allies, that this is a problem that has to be addressed and that we can't delay addressing it," White House spokesman Robert Gibbs said.

Iran insists it is using its enrichment programme only to supply domestic power reactors with fuel.

The report was released to IAEA member states amid recent signs from US President Barack Obama that the two countries might be interested in ending three decades of political estrangement and resume direct talks on Iran's nuclear programmes, along with topics such as the conflicts in Afghanistan and Iraq.

Iranian President Mahmoud Ahmadinejad said Tuesday that his country would not suspend its controversial nuclear-enrichment programme for the sake of improving ties with the United States.

The IAEA report released Thursday also showed that Iran has slowed the expansion of its uranium-enrichment programme, but the country still is not cooperating fully.

The report by IAEA head Mohamed ElBaradei stated that since last November only 164 additional centrifuges have started producing low- enriched uranium. Currently,
3,936 such machines are operating, the report said.

The IAEA has received intelligence from several member states indicating that past research into high explosives, missile design and uranium metal could have been geared toward nuclear weapons work. (dpa)