Iran has obtained technology to make more "accurate" centrifuges for the final stage of nuclear fuel production, Reuters quotes a senior Iranian official.

The claim comes as Iranian President Mahmoud Ahmadinejad inaugurated a new facility Thursday producing uranium fuel for a planned heavy-water nuclear reactor. The West fears the reactor could eventually be used for producing a nuclear weapon.

Officials said the number of centrifuges at Iran's uranium enrichment facility had increased to 7,000 — up from 6,000 announced in February — and that two new, more advanced types of centrifuge had been tested, Reuters reported.

Ahmadinejad announced the plant's opening during a ceremony in the central city of Isfahan. The plant will produce pellets of uranium oxide to fuel the heavy-water research reactor, which is scheduled to be completed in 2009 or 2010.

Iran denies any intention to build a nuclear weapon. The U.S. and its allies have expressed concerns Iran could reprocess spent fuel from the heavy-water reactor into plutonium for building a warhead.

The process is distinct from uranium enrichment, which produces fuel for a light-water reactor. Highly enriched uranium can be used to build a warhead as well. Iran's enrichment program presents more immediate concerns to the West than the hard-water reactor, because it is far more advanced.

The announcement comes a day after the United States announced it would participate directly in group talks with Iran over its nuclear program, another significant shift from President George W. Bush's policy toward a nation he labeled part of an axis of evil. Britain, China, France, Germany and Russia announced Wednesday they were inviting Iran to a new session of negotiations aimed at breaking a deadlock in the talks.

Iran has not yet replied to the invitation. Tehran has rejected U.N. demands it halt uranium enrichment, saying it has a right to develop nuclear technology for a program it says is peaceful, aimed only at producing electricity.

Ahmadinejad was attending celebrations for Iran's National Day of Nuclear Technology, which marks the day in 2006 when Iran enriched uranium for the first time.

Iran has been building the 40-megawatt hard-water reactor in the central town of Arak for the past four years. Hard-water reactors do not need enriched uranium for fuel, and can instead use more easily produced uranium oxide ore, fashioned into pellets.

The Associated Press contributed to this report.