(LtoR) US Secretary of State John Kerry, US Secretary of Energy Ernest Moniz and US Under Secretary for Political Affairs Wendy Sherman wait for a meeting during Iran nuclear talks, on March 30, 2015 in Lausanne. The top diplomats of Iran and United States, China, Russia, Britain, France and Germany aim by the end of March 31 to agree the outlines of a deal curtailing Iran's nuclear programme.  AFP PHOTO / FABRICE COFFRINI        (Photo credit should read FABRICE COFFRINI/AFP/Getty Images)