Nadergholi Ebrahimi has asked Supreme Leader Khamenei to rethink Iran's nuclear policy if negotiations with the U.S. collapse.

Tehran called Sunday’s meeting “difficult but useful” as the two sides clash over future of Iran’s uranium enrichment.

Suspected Islamist militants attacked a Nigerian army base and captured soldiers and ammunition during a raid in the insurgency-hit northeastern Borno state in the early hours of Monday, two security sources told Reuters.