Du Jingchen, deputy commander of the Navy of the People's Liberation Army of China delivers a speech during the joint press conference in Novorossiysk, Russia, on May 21, 2015. Chinese and Russian naval forces on Thursday ended their joint military exercises in the Mediterranean, according to an online news briefing from the Chinese Defense Ministry. (Xinhua/Dai Tianfang)

Du Jingchen(R), deputy commander of the Navy of the People's Liberation Army of China shakes hands with Alexander Fedotenkov, deputy commander of the Russian Navy during a joint press conference in Novorossiysk, Russia, on May 21, 2015. Chinese and Russian naval forces on Thursday ended their joint military exercises in the Mediterranean, according to an online news briefing from the Chinese Defense Ministry. (Xinhua/Dai Tianfang)

Du Jingchen(R), deputy commander of the Navy of the People's Liberation Army of China and Alexander Fedotenkov, deputy commander of the Russian Navy attend a joint press conference in Novorossiysk, Russia, on May 21, 2015. Chinese and Russian naval forces on Thursday ended their joint military exercises in the Mediterranean, according to an online news briefing from the Chinese Defense Ministry. (Xinhua/Dai Tianfang)

Photo taken on May 21, 2015 shows the closing ceremony of the joint naval exercises in Novorossiysk, Russia. Chinese and Russian naval forces on Thursday ended their joint military exercises in the Mediterranean, according to an online news briefing from the Chinese Defense Ministry. (Xinhua/Dai Tianfang)