Head of the President’s Office of Ukraine Andriy Yermak, Foreign Minister Andriy Sybiha and Defense Minister Rustem Umerov held a meeting in Istanbul on Friday with Special Representative of the US President Keith Kellogg, National Security Adviser to the Prime Minister of Great Britain Jonathan Powell, Adviser to the Chancellor of Germany on Foreign Policy and Security Günter Sautter and Diplomatic Adviser to the President of France Emmanuel Bonne.