Indirect talks between Tehran and Washington to revive the 2015 Iran nuclear deal are in the home straight, delegates say, though some important issues remain unresolved and it is still unclear whether an agreement will be clinched.
Since then-President Donald Trump pulled the United States out of the accord in 2018 and reimposed sanctions, Iran has breached many of the deal's curbs that had extended the time it would need to produce enough fissile material for an atom bomb - if it chose to build one - to at least a year from 2-3 months.
