U.S. Secretary of State John Kerry arrives at Geneva International airport November 8, 2013. Iran and six world powers are making progress in negotiations aimed at ending a decade-long stand-off over its nuclear ambitions but the discussions are “tough”, Tehran’s foreign minister Mohammad Javad Zarif said on Thursday, after a first session in the two-day talks in Geneva. REUTERS/Denis Balibouse (SWITZERLAND – Tags: POLITICS ENERGY)