Iran is currently carrying out experiments with advanced centrifuges in its Natanz nuclear facility, western diplomats in Vienna with access to privileged intelligence on the matter told news agencies Wednesday.

"The Iranians have begun a trial run of the advanced model [of centrifuges]," one of the diplomats said. "It is still not known what stage of the experiments they are at," the source added.

The centrifuges are reportedly an advanced model, named P-2, which is technologically superior to the P-1 centrifuges currently in Iranian use. Iran announced three months ago that 3,000 of the P-1 centrifuges were already operational.