The United States still believes that Iran has not decided to build a nuclear weapon despite Tehran's recent strategic setbacks, including Israel's killing of Hezbollah leaders and two largely unsuccessful attempts to attack Israel,

Nuclear experts see Tehran as facing up to a year of hard work to master the knotty basics of building a deliverable atom bomb.

The history of other countries’ weapons programs shows that Tehran could complete and deploy a missile-deliverable warhead in a matter of months.