Ukrainian President Petro Poroshenko prepares to speak at a news conference during the NATO summit at the Celtic Manor resort, near Newport, in Wales September 4, 2014. NATO demanded on Thursday that Moscow withdraw its troops from Ukraine as U.S. President Barack Obama and his Western allies held a summit intended to buttress defences against Russia in the biggest strategic shift since the Cold War. REUTERS/Rebecca Naden (BRITAIN - Tags: MILITARY POLITICS)