The operation was carried out in secret to maintain plausible deniability and to resist the expansionist efforts of Japan to establish itself as the pre-eminent political force in East Asia. Under the name of Soviet Air Force Volunteers, Soviet troops fought in the defense of Nanjing, Wuhan, Nanchang, and Chongqing. Over 250 Soviet volunteer pilots and 885 aircraft were provided to China. The aircraft included Polikarpov I-15, Polikarpov I-16, and Polikarpov I-153.