Iranian security forces stand guard as tens of thousands of Iranians gather in Azadi (Freedom) Square in southwestern Tehran to listen to a speech by President Mahmoud Ahmadinejad, marking the 31st anniversary of the Islamic revolution on February 11, 2010. Ahmadinejad said Iran has produced a "first stock" of 20 percent enriched uranium for its nuclear programme and is capable of enriching it to 80 percent but will not do so. AFP PHOTO/ATTA KENARE (Photo credit should read ATTA KENARE/AFP/Getty Images)