European Union foreign policy chief Ashton and Iranian Foreign Minister Zarif smile at start of talks in Vienna

European Union foreign policy chief Catherine Ashton (L) and Iranian Foreign Minister Mohammad Javad Zarif smile at the start of talks in Vienna April 8, 2014. Iran and six world powers began a new round of negotiations on Tuesday aimed at settling the dispute over Tehran’s nuclear programme by late July, despite wide differences on how to get there. REUTERS/Heinz-Peter Bader (AUSTRIA – Tags: POLITICS ENERGY)

Iran, six powers face ‘significant gaps’ in nuclear talks