Washington wants to be certain that any nuclear deal between Iran and major powers includes the possibility of restoring U.N. sanctions if Tehran breaks the agreement without risking Russian and Chinese vetoes, a senior U.S. official said on Tuesday. United Nations sanctions and a future mechanism for Iran to buy atomic technology are two core sticking points in talks on a possible nuclear deal on which Tehran and world powers have been struggling to overcome deep divisions in recent days, diplomats said on condition of anonymity. Negotiators were wrapping up nearly a week of talks in New York on Tuesday, the latest round in 18 months of discussions aimed at clinching a long-term deal by June 30 to curb Iran’s nuclear program in exchange for an end to sanctions. Expert-level negotiations are expected to continue for several days. The current talks have been taking place […]