U.S. Under Secretary for Political Affairs Wendy Sherman (L-R), U.S. Secretary of Energy Ernest Moniz, U.S. Secretary of State John Kerry and Atomic Energy Agency (IAEA) Director General Yukiya Amano, meet at a hotel in Vienna, Austria June 29, 2015. Iran is backtracking from an interim nuclear agreement with world powers three months ago, Western officials suggested on Sunday, as U.S. and Iranian officials said talks on a final accord would likely run past a June 30 deadline. REUTERS/Carlos Barria