Mongolian Operation of 1921

the combat operations of Soviet and Mongolian troops to wipe out the White Guard bands of General R. F. Ungern von Sternberg. The operation consisted of a defensive phase (May and June) and an offensive phase (June to August). In May 1921, Ungern’s forces, composed of White cossacks and detachments organized by Mongolian feudal chiefs (about 10,550 horse, 200 foot, 37 machine guns, and 21 artillery pieces), attacked Soviet border troops at several points. The main White Guard forces advanced along both banks of the Selenga River on Troitskosavsk and Kiakhta. Through the joint operations of units of the 35th Division of the Fifth Red Army, commanded by M. S. Matiiasevich, the People’s Revolutionary Army of the Far East Republic (FER), and Mongolian people’s revolutionary forces, the enemy was repulsed and retreated into the interior of Mongolia.

In mid-June, at the request of the Provisional People’s Government of Mongolia, the Soviet command began preparing an offensive to destroy the White bands and liberate Mongolia. An expeditionary corps of the Fifth Army was formed under the command of K. A. Neiman (7,600 foot, 2,500 horse, 20 artillery pieces, two armored trains, four airplanes). On June 27, units of the expeditionary corps, acting in coordination with the People’s Revolutionary Army of the FER and the Mongolian people’s revolutionary army under the command of Sukhe-Bator, launched an offensive. The main forces (5th Cavalry Division, 103rd Infantry Brigade, and Mongolian regiments) advanced on Urga. On the west their actions were protected by the 105th Infantry Brigade, the 35th Cavalry Regiment, and Choibalsan’s Mongolian cavalry detachment, and on the east they were covered by the Second Sretensk Cavalry Brigade of the People’s Revolutionary Army of the FER. In ten days of continuous fighting the troops advanced about 350 km, liberating Urga on July 6. The remnants of Ungern’s troops (about 4,000 horse, 6–8 artillery pieces, and 18–20 machine guns) retreated to VanKuren, 75 km from the Soviet border.

From July 18 to 21, Soviet and Mongolian troops fought fierce battles with the enemy. Nevertheless, the mobility of its cavalry enabled the enemy to break away from the Soviet and Mongolian forces. Between July 24 and August 3, Ungern’s detachments again entered Soviet territory north of Lake Gusinoe, but after suffering heavy losses, they began to retreat on August 3. The White Guard forces began to disintegrate, and Ungern was captured with a small detachment. The remnants of the enemy forces were annihilated in the region east and southeast of Urga. Thanks to the help of the Red Army the Mongolian people established and consolidated their national people’s government.