Iran has built a new generation of centrifuges for enriching uranium and is testing them, the official news agency IRNA quoted its nuclear energy agency chief as saying on Tuesday.

"Iranian scientists have made a new generation of centrifuges that are currently undergoing necessary tests," Ali Akbar Salehi told a Tehran news conference as reported by IRNA.

"Chains of 10 centrifuges are now under test," he said, and the number in each chain "will be gradually increased."

Salehi did not say when the new model of centrifuge would be introduced to the production line in its Natanz enrichment plant but said it was stronger and faster than those now in operation.

Iran says it is enriching uranium only to low levels suitable for electricity generation and is committed to non-proliferation safeguards maintained by inspectors from the International Atomic Energy Agency.

United States and some Western countries suspect Iran has a secret project to fuel atomic bombs with highly enriched uranium, something the Islamic Republic has repeatedly denied.

A senior diplomat close to the IAEA said there appeared to be little new in Salehi's announcement. The IAEA has reported Iran testing advanced models of centrifuges for more than two years but found no sign of them being phased into production lines.

An August 28 IAEA report said Iran had actually somewhat reduced the number of older-model P-1 centrifuges enriching uranium in a step diplomats said appeared to be related to needed repair and maintenance work.

But the report said Iran had raised the number of installed, although not yet all running, centrifuges to more than 8,300, boosting its potential nuclear fuel production capacity.

World powers base their assessment of possible proliferation risk posed by Iran on the number of centrifuges installed.   

The UN Security Council has demanded that Iran suspend its enrichment activities because of unresolved concerns about its nuclear ambitions, but Tehran has refused.

Iran is due to hold talks on October 1 with six world powers.-Reuters