"Iran can now mass-produce centrifuges. This is an important success, because no other country was willing to sell us this technology," a deputy head of Iran's Atomic Energy Organisation, Hossein Faghihian, was quoted as saying in Iranian media.

Centrifuges are used to enrich uranium for either nuclear reactor fuel or atomic bomb material. They work in cascades of hundreds, or thousands, spinning at high speed to refine out the uranium U-235 isotope.

Enrichment is seen as a "breakout capacity", because once mastered the manufacturing of nuclear weapons becomes possible. Iran says such work is legal, but Western powers argue the clerical regime cannot be trusted with it.

France and Britain on Wednesday circulated a draft resolution in the Security Council that would legally oblige Iran to comply with UN demands that it freeze uranium enrichment.

The text, worked out in close consultations with Germany and the United States, invokes Chapter 7 of the UN Charter, which can authorize economic sanctions or even as a last resort the use of force in cases of threats to international peace and security.

For the time being, Russia and China -- who both have veto powers on the Council -- appear to be opposed to such a text.

Thursday's news on centrifuge development follows a string of other claims of nuclear progress.

Earlier this week, Iran's vice president and Atomic Energy Organisation director Gholam Reza Aghazadeh said new uranium deposits had been found close to the southern Gulf port of Bandar Abbas and in the northeast of the country.

He said the discoveries would be more economical to exploit than an existing mine at Saghand in the central province of Yazd.

On Tuesday, Aghazadeh also said Iran has managed to enrich uranium up to 4.8 percent purity, around the level needed to make reactor fuel. That announcement came just weeks after Iran declared it had joined the "world atomic club" by enriching to 3.5 percent.

This is still way below the levels of purity of more than 90 percent needed to produce the fissile core of an atom bomb, and Aghazadeh insisted that "enrichment of more than five percent is not on Iran's agenda".

"Construction work and preparation of centrifuge machines are being done to create a 3,000-centrifuge cascade," he also said.

At present Iran is using a cascade of 164 centrifuges installed at a pilot plant in Natanz. Although Iran is so far only using less advanced P-1 centrifuges, a week ago another nuclear official said Iran was working on far more advanced designs.

"We have told the (International Atomic Energy) Agency that we are studying and conducting research on different types of machines. We cannot limit ourselves when we have an enrichment programme," Mohammad Saidi, also a senior official in Iran's Atomic Energy Organisation, said last Saturday.

"But when it comes to which type we will use, we are still examining this. It isn't the P-2 (centrifuge). There are other devices that are more advanced and that are a part of our work," he added.

The more advanced P-2 centrifuge can enrich at a much faster rate and is considered far more effective than the P-1 in the production of weapons-grade material.

Iran is suspected of acquiring P-2 devices on the black market network of disgraced Pakistani nuclear scientist Abdul Qadeer Khan, the father of the country's atom bomb.

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