Tehran, Iran ? President Mahmoud Ahmadinejad announced major progress in Iran’s push for nuclear power, saying Tuesday that his nation was installing thousands of new uranium-enriching centrifuges and testing a much faster version of the device.

Ahmadinejad said scientists were putting 6,000 new centrifuges into place, about twice the current number, and testing a new type that works five times faster.

That would represent a major expansion of uranium enrichment – a process that can produce either fuel for a nuclear reactor or material for a warhead. Secretary of State Condoleezza Rice cautioned, however, that the claim could not be immediately substantiated.

Diplomats close to the U.N. nuclear watchdog agency say Iran has exaggerated its progress and seen problems operating the 3,000 centrifuges already in place. One diplomat said Ahmadinejad’s claims of a more advanced centrifuge appeared to allude to a type known as the IR-2, which the agency and Iran said months ago that Iran had begun testing.

While expressing concern that Iran continued to defy a U.N. Security Council ban on enrichment, a diplomat said that Ahmadinejad’s an-nouncement “seems to be little more than a publicity stunt.” He spoke on condition of anonymity because he was not authorized to comment publicly.

The IR-2 is believed to be two to three times faster than the centrifuges currently in use, and his claim that the new machine was five times as quick added to the skepticism of the diplomats.

Permanent members of the Security Council, which has already imposed three sets of sanctions against Iran for its refusal to suspend uranium enrichment, were divided in their response to the announcement.

The United States and Britain quickly condemned it, and France warned that Iran could face more sanctions. But Russia, an ally of Iran, dismissed the need for that, saying negotiators were preparing a new package of incentives aimed at persuading Iran to freeze uranium enrichment.

Iran rejected a standing package of incentives endorsed by the five Security Council members plus Germany last week. Tehran says its nuclear program is intended only to produce energy, not develop weapons as the U.S. and many of its allies fear.

Iran has about 3,000 centrifuges operating at its underground nuclear facility in Natanz. That is the commonly accepted figure for a nuclear enrichment program that is past the experimental stage and can be used as a platform for a full industrial-scale program that could churn out enough enriched material for dozens of nuclear weapons over time.

During a tour of the Natanz facility in ceremonies marking the second anniversary of Iran’s first enrichment of uranium, Ahmadinejad an-nounced the start of work on installing the new centrifuges.