A Russian navy vessel arrives at Dagang port of Qingdao, east China's Shandong Province, April 29, 2019. Russian naval vessels arrived in Qingdao on Monday to participate in the Sino-Russian "Joint Sea-2019" exercise. The exercise will focus on joint sea defense, which aims to consolidate and develop the China-Russia comprehensive strategic partnership of coordination, deepen pragmatic naval cooperation, and improve their capabilities to jointly respond to security threats at sea. Two submarines, 13 surface ships, as well as fixed-wing airplanes, helicopters and marines, will participate in the exercise. (Xinhua/Li Ziheng)