"(From L) EU's foreign policy chief Federica Mogherini, Iranian Foreign Minister Mohammad Javad Zarif, Deputy director of the Department for Nonproliferation and Arms Control of the Ministry of Foreign Affairs of Russia Alexey Karpov, British Foreign Secretary Philip Hammond and US Secretary of State John Kerry attend the announcement of an agreement on Iran nuclear talks on April 2, 2015 at the The Swiss Federal Institutes of Technology (EPFL) in Lausanne. Iran and world powers said they had reached agreement on Thursday on ""key parameters"" of a potentially historic deal aimed at preventing Tehran from building the bomb. AFP PHOTO / FABRICE COFFRINI        (Photo credit should read FABRICE COFFRINI/AFP/Getty Images)"