12th Army ( Soviet Union ) The Soviet Union ' s 12th Army was a field army formed multiple times during the Russian Civil War and World War II . Civil War & Polish - Soviet War . The 12th Army ( Russian Civil War 1st Formation ) of the Soviet Red Army was first formed from Soviet forces in the north - eastern Caucasus in 1918 . The 12th Army ( Russian Civil War 2nd Formation ) was formed from the 1st and 3rd Ukrainian Red Armies in central Ukraine in the summer of 1919 . In July 1920 Simon Aralov was chief of intelligence with this unit . Second World War . The 12th Army ( 1st Formation ) ( RKKA ) of the Soviet Red Army was formed from the Southern ( Cavalry - Mechanised ) Army Group of the Kiev Special Military District during 1939 - 40 . It was then involved in the Soviet invasion of Poland ( 1939 ) . It entered the Second World War as part of the Soviet Southwestern Front , comprising the 13th Rifle Corps ( including the 44th , 58th , and 192nd Rifle Division s ) 17th Rifle Corps ( 60th Mountain , 69th Mountain , and 164th Rifle Divisions ) , 16th Mechanised Corps ( 15th , 39th Tank Division s , 240th Mechanised Division ) 10th , 11th and 12th Fortified Regions , and artillery , engineering and other units . It participated in the frontier battle to the west of Stanislav . In the second half of July as part of the Soviet Southern Front it conducted defensive fights in the direction of Uman . During the Battle of Uman , the Twelfth Army was caught in a huge encirclement south of Kiev along with the 6th Army . Thus the army ' s headquarters was disbanded on 10 August 1941 , after the battle . The 12th Army was reformed in August 1941 as part of the Soviet Southern Front on the basis of 17th Rifle Corps . On 1 September 1941 its structure included 270th and 274th Rifle Division s , the 11th Tank Division , 268th and 374th Corps Artillery Regiments , 64th and 181st Fighter Aviation Regiments , and a number of separate formations . The Army defended the left coast of the Dnepr around Zaporozhye , from the end of September to the beginning of December , 1941 . It participated in the Donbass defensive , Rostov defensive and offensive , in January , 1942 in the Barvenkovo - Lozove offensive operations , in the subsequent conducted defensive fights in Donbass and on Northern Caucasus ( part of the Battle of the Caucasus ) . In the middle of April 1942 the 261st Rifle Division under Colonel A . M . Ilina , the 4th Rifle Division ( Colonel I . P . Roslogo ) , the 74th Rifle Division under General F . E . Sheverdina , the 176th Rifle Division ( General V . N . Martsinkevicha ) and 54th Tank Brigade ( тбр ) under Colonel K . S . Minarova were assigned to the Army . It was later in 1942 reorganised as a defensive zone HQ , but then reformed again by conversion of the previous 5th Tank Army in mid April 1943 . It joined the Southwestern Front . Its structure included the 172nd , 203rd , 244th , 333rd and 350th Rifle Divisions and other formations . In April - July the Army was in Front reserve , and then participated in the Donbass and Zaporozhye offensive operations . In November the army HQ was disbanded , with its forces transferred to other armies . Commanders included Lieutenant - General I . Shlemin ( April - May 1943 ) , and Major - General Danilov ( May - October 1943 ) .