IAEA: Iran has activated enrichment equipment

VIENNA - Iran has activated equipment to enrich uranium more efficiently, according to the International Atomic Energy Agency, while its senior leadership on Monday directly called for negotiations over nuclear weapons.

The Vienna-based nuclear watchdog also said on Monday that Iran has started using a second set of 164 centrifuges linked in a cascade, or string of machines, to enrich uranium to up to 20 percent at its Natanz pilot fuel enrichment plant - in defiance of the UN Security Council. Another cascade there has been producing uranium enriched to near 20 percent since February.

If enriched to near 95 percent, uranium can be used in building a nuclear bomb. At 20 percent, it may also be turned into weapons-grade material much more quickly than less-enriched uranium.