An armed helicopter fleet launches an assault on the defense works and firing points of the mock terrorists during the low-altitude defense penetration operations in the China-Russia joint military exercise ZAPAD/INTERACTION-2021 at a training base of the PLA Army in Qingtongxia City of West China's Ningxia Hui Autonomous Region from August 9 to 13, 2021. (eng.chinamil.com.cn/Photo by Wang Weidong)
