Washington, DC [US], May 18 (ANI): A top US defence official has warned his Chinese counterpart about China’s increasing cooperation with Russia, even as Chinese President Xi Jinping and Russian President Vladamir Putin met and pledged to strengthen ties between the two countries. Ely Ratner, US Assistant Secretary of Defence for Indo-Pacific Security Affairs, spoke by video teleconference with China’s) Major General Li Bin, Director of the Central Military Commission Office for International Military Cooperation, on Friday. Ratner discussed the relationship between Russia and North Korea as w…