Iran Moving to 'Threshold' of Making Atom Bomb, U.S. Official Says

A senior U.S. government official says Iran is moving toward the threshold of being able to build a nuclear weapon, but Tehran's leaders may be divided over whether to take the final step and actually make one.

State Department special adviser Robert Einhorn told a conference Wednesday that Iran is seeking at a minimum to have the option of building a nuclear weapon. Einhorn said Iran may not have made the political decision to build one and that the country is not close to a "breakout" of being able to construct one in a short time.

Einhorn said the international sanctions against Iran adopted last year are already taking a big toll against the country, but so far Iran has not shown a willingness to negotiate seriously.