Iran begins installing 6,000 new centrifuges

State television is quoting Iranian President Mahmoud Ahmadinejad saying that Iran has begun installing 6,000 centrifuges at its uranium enrichment plant in Natanz. Iran already has about 3,000 centrifuges operating in Natanz and the new announcement is seen as a show of defiance of international demands to halt a nuclear program. The US and its allies say the program is aimed at building nuclear weapons.