Initially during the native revolts of the early 1930s and the Japanese border probes beginning in the mid-1930s, Soviet Red Army troops in Mongolia amounted to little more than instructors for the native army and as guards for diplomatic and trading installations.
However, in the 1939 Battles of Khalkhin Gol (or Nomonhan) heavily armed Red Army forces under Georgy Zhukov assisted by Mongolian troops under Khorloogiin Choibalsan decisively defeated Imperial Japanese Army forces under Michitarō Komatsubara.