The flag of the International Atomic Energy Agency (IAEA) flies in front of its headquarters in Vienna, Austria, May 28, 2015. Iranian Foreign Minister Mohammad Javad Zarif said on Thursday he hoped Tehran and world powers would reach a final nuclear deal "within a reasonable period of time" but this would be hard if the other side stuck to what he called excessive demands. REUTERS/Heinz-Peter Bader TPX IMAGES OF THE DAY