Chinese and foreign officers work together during a joint naval exercise on the sea off Qingdao, east China's Shandong Province, on April 26, 2019. China conducted a joint naval exercise with Southeast Asian countries in Qingdao, with focus on jointly handling pirate threats and maritime emergency rescues. (Photos: Xinhua)

Chinese and foreign officers talk during a joint naval exercise on the sea off Qingdao, east China's Shandong Province, on April 26, 2019. China conducted a joint naval exercise with Southeast Asian countries in Qingdao, with focus on jointly handling pirate threats and maritime emergency rescues.

Chinese naval logistics vessel Taihu participates in a joint naval exercise on the sea off Qingdao, east China's Shandong Province, on April 26, 2019. China conducted a joint naval exercise with Southeast Asian countries in Qingdao, with focus on jointly handling pirate threats and maritime emergency rescues.

Chinese navy soldiers salute to bid farewell after a joint naval exercise on the sea off Qingdao, east China's Shandong Province, on April 26, 2019. China conducted a joint naval exercise with Southeast Asian countries in Qingdao, with focus on jointly handling pirate threats and maritime emergency rescues.

A helicopter takes off from a Chinese naval vessel during a joint naval exercise on the sea off Qingdao, east China's Shandong Province, on April 26, 2019. China conducted a joint naval exercise with Southeast Asian countries in Qingdao, with focus on jointly handling pirate threats and maritime emergency rescues.

Naval vessels take part in a joint naval exercise on the sea off Qingdao, east China's Shandong Province, on April 26, 2019. China conducted a joint naval exercise with Southeast Asian countries in Qingdao, with focus on jointly handling pirate threats and maritime emergency rescues.

Chinese soldiers head for a foreign naval vessel during a joint naval exercise on the sea off Qingdao, east China's Shandong Province, on April 26, 2019. China conducted a joint naval exercise with Southeast Asian countries in Qingdao, with focus on jointly handling pirate threats and maritime emergency rescues.

Naval vessels take part in a joint naval exercise on the sea off Qingdao, east China's Shandong Province, on April 26, 2019. China conducted a joint naval exercise with Southeast Asian countries in Qingdao, with focus on jointly handling pirate threats and maritime emergency rescues.

A helicopter is about to land on a Chinese naval vessel during a joint naval exercise on the sea off Qingdao, east China's Shandong Province, on April 26, 2019. China conducted a joint naval exercise with Southeast Asian countries in Qingdao, with focus on jointly handling pirate threats and maritime emergency rescues.

Soldiers are seen on a naval vessel during a joint naval exercise on the sea off Qingdao, east China's Shandong Province, on April 26, 2019. China conducted a joint naval exercise with Southeast Asian countries in Qingdao, with focus on jointly handling pirate threats and maritime emergency rescues.

A helicopter is seen on a Chinese naval vessel during a joint naval exercise on the sea off Qingdao, east China's Shandong Province, on April 26, 2019. China conducted a joint naval exercise with Southeast Asian countries in Qingdao, with focus on jointly handling pirate threats and maritime emergency rescues.