Iran has started up advanced centrifuges to boost the country's stockpile of enriched uranium, its atomic energy organization spokesman Behrouz Kamalvandi said on Saturday.

The agency activated 20 IR-4 and 20 IR-6 centrifuges, Kamalvandi told a televised news conference in Tehran, as a third step in Iran's reduction of its commitments under a 2015 nuclear deal. He added that Iran has the capacity to enrich uranium up to 20 percent.

Kamalvandi also said Iran will allow the UN atomic agency to continue monitoring its nuclear program, as it detailed its latest reduction of its commitments under a 2015 accord.

"Regarding the monitoring and accesses of the IAEA (International Atomic Energy Agency)... so that everything is clear (Iran's) commitments regarding transparency will be followed as before," said Kamalvandi.

Reporting by AFP, Reuters