Iran's new generation of advanced centrifuges have begun processing small quantities of the gas that can be used to make the fissile core of nuclear warheads, diplomats told The Associated Press on Wednesday. The diplomats emphasized that the centrifuges were working with only minute amounts of the uranium gas used as the feed stock for Iran's uranium enrichment program. And one of them said Teheran had set up only 10 of the machines - far too few to produce enriched uranium in the quantities needed for an industrial scale energy or a weapons program. Still, the information revealed previously unknown details of the state of the Islamic Republic's experiments with its domestically developed IR-2 centrifuges, which can churn out enriched uranium at more than double the rate of the machines that now form the backbone of its nuclear project. The existence of the IR-2 was made known only last week by diplomats accredited to the Vienna-based International Atomic Energy Agency probing Iran's nuclear program for suspicions it may have been designed to make weapons. But diplomats back then told the AP that the machines appeared to be running empty and could not quantify the number of the centrifuges had been set up at the experimental facility linked to Iran's growing enrichment underground enrichment plant at Natanz. Fleshing out previous information, one of the diplomats said Wednesday that the centrifuges were set up Jan. 20 and began processing minute amounts of the uranium gas soon afterward as part of testing the machines. He and others accredited to the IAEA demanded anonymity because their information was confidential. Iran is under two sets of UN Security Council sanctions for refusing to suspend uranium enrichment, which it started developing during nearly two decades of covert nuclear activity built on illicit purchases and revealed only five years ago. That secrecy heightened suspicions about Iran's intent, but Iranian leaders argued the country has a right to run a peaceful enrichment program to generate electricity and dismissed the UN demands, saying they planned to expand the project rather than freeze it. Until last week's revelations that Iran had developed its own advanced centrifuge, Iran had publicly focused on working with P1 centrifuges - outmoded machines that it acquired on the black market in the 1980s. More than 3,000 of the older centrifuges are operating in the large underground hall near Natanz, a city nearly 500 kilometers south of Teheran. In related news, Russia's foreign minister said Wednesday that Moscow disapproved of Iran's uranium enrichment efforts and its missile program. "We don't approve of Iran's continuously demonstrating its intentions to develop its missile industry and continue uranium enrichment," Sergey Lavrov told Russian news wires on his way back from Slovenia. "From the point of view of international law, these activities aren't forbidden. However, it's necessary to take into account that the past years have shown a number of problems related to Iran's nuclear program."