TEHRAN, Iran—Iran announced Sunday that it has begun enriching uranium up to 20 percent using sophisticated centrifuges at its underground Fordo nuclear plant, state TV reported, an escalation that comes amid a standoff with the West over its tattered atomic deal.
That Tehran is enriching uranium up to 20 percent purity—a technical step from weapons-grade levels of 90 percent—with a new set of its most advanced centrifuges at a facility deep inside a mountain deals yet another blow to the already slim chances of reviving the accord.
