SWITZERLAND-IRAN-US-NUCLEAR-POLITICS

U.S. Secretary of State John Kerry walks back into the hotel after a morning meeting with Iran's Foreign Minister over Iran's nuclear programme in Lausanne March 19, 2015. US and Iranian negotiators entered into a fourth day of tough talks towards a landmark nuclear deal, with Tehran's foreign minister talking down prospects for a breakthrough this week. US Secretary of State John Kerry and his Iranian counterpart have been haggling in Switzerland since Monday as they seek to agree the outlines of this potentially historic agreement by March 31. AFP PHOTO / POOL / Brian Snyder (Photo credit should read BRIAN SNYDER/AFP via Getty Images)