Iran has produced “a few tons” of the gas needed to enrich uranium, a top nuclear official said Wednesday, confirming the country has defied international demands and taken a necessary step toward producing nuclear fuel — or nuclear weapons. Uranium hexafluoride gas is the material that, in the next stage, is fed into centrifuges used to enrich uranium. Uranium enriched to a low level is used to produce nuclear fuel to generate electricity and enriched further can be used to manufacture atomic bomb. Full Story