International negotiators are holding key talks with Iran that could see it handing over most of its enriched uranium for processing abroad.
Iran would not have enough material for a nuclear weapon if it exported most of its enriched uranium. Western nations suspect Tehran of seeking to build a weapon, but Iran denies that.
Monday's talks, conducted in Geneva, follow a meeting between six world powers and Iran earlier this month. The West says that Iran agreed to transfer the uranium to Russia and have it turned into fuel for a small research reactor.
Monday's talks involve the US, Russia, France, Iran and experts from the International Atomic Energy Agency.