An anti-submarine rocket is launched from the guided-missile frigate Wuhu of the Chinese People's Liberation Army (PLA) Navy on May 3, 2019. The Sino-Russia Joint Sea 2019 naval exercise lasted from April 29 to May 4. (Photos: China Plus)

Two anti-submarine rockets are launched from the guided-missile frigate Wuhu of the Chinese PLA Navy on May 3, 2019. The Sino-Russia Joint Sea 2019 naval exercise lasted from April 29 to May 4.

Chinese and Russian navy vessels sail in formation on May 3, 2019 during the Sino-Russia Joint Sea 2019 naval exercise. The event lasted from April 29 to May 4.

Artillery is fired from the guided-missile frigate Wuhu of the Chinese PLA Navy on May 4, 2019. The Sino-Russia Joint Sea 2019 naval exercise lasted from April 29 to May 4.

A helicopter lands on the guided-missile frigate Wuhu of the Chinese PLA Navy on May 3, 2019. The Sino-Russia Joint Sea 2019 naval exercise lasted from April 29 to May 4.

Chinese navy sailors wave to see off the Russian fleet on May 4, 2019. The Sino-Russia Joint Sea 2019 naval exercise lasted from April 29 to May 4.