From the AP -
Iran's president says Iran has begun installing 6,000 centrifuges at its uranium enrichment plant in Natanz. Mahmoud Ahmadinejad announced the work on state television on Tuesday. Iran already has about 3,000 centrifuges operating in Natanz. The new announcement is seen as a show of defiance of international demands to halt a nuclear program. The U.S. and its allies say the program is aimed at building nuclear weapons. Iran denies those allegations.