First formation The Leningrad Military District was directed to form the 1st Mechanized Corps from the 20th Heavy Tank Brigade, the 1st and 13th Light Tank Brigades, the
25th Cavalry Division, and the
163rd Rifle Division, which was converted to the 163rd Motorized Division beginning on July 1. The formation of the corps was to be completed by 30 June 1940, but the reorganization was interrupted by the
Soviet invasion of Estonia. For the latter, the 13th Light Tank Brigade moved to Pskov by 13 June, assigned to the 8th Army. The corps was initially formed in March 1940 attached to the
Leningrad Military District, and held in reserve near the Pskov Fortified Region. It was under the command of Major General when the German
Operation Barbarossa began in June 1941. It initially comprised the
1st and
3rd Tank Divisions, and the
168th Rifle Division. The 3rd Tank Division of the corps was formed from the
13th Light Tank Brigade; the new division inherited the brigade's Order of the Red Banner. The brigade's 6th and 9th Tank Battalions were used to form the 5th Tank Regiment and the 13th and 15th Tank Battalions the 6th Tank Regiment. The period for the formation of the corps was lengthened on 23 June with the extension of the deadline for the completion of the process to 31 July. Despite these delays, the formation of the first new mechanized corps was completed by October and the 1st became one of the most well-manned and -equipped due to the number of units used to form it. On 22 June 1941, 1st Mechanized Corps consisted of 31,439 men, 1,037 tanks, 239 armored cars, 148 artillery pieces, 146 mortars, 4,730 vehicles, 246 tractors, and 467 motorcycles; including lighter
T-26,
BT-7, and
T-28 model tanks. After the invasion began, the
Leningrad Military District was renamed to the
Northern Front and was overseen by
Lieutenant General Markian M. Popov. The front fielded the
14th,
7th, and
23rd Armies, the 65th Rifle Corps and the Leningrad Military District forces, including the 2nd Division of NKVD troops. The 1st Mechanized Corps was heavily engaged in the first battles of
Operation Barbarossa, particularly during the
Baltic Operation (1941). On 29 June 1941, the 1st Mechanized Corps was ordered to reinforce new defenses anchored on the
Velikaya River, near
Ostrov, on the former
Stalin Line after the spectacular advances by
Georg-Hans Reinhardt's
XLI Panzer Corps, which had crossed the
Daugava River. However it was unable to hold the line. On 11 July 1941, Colonel on the Northwestern Front reported that the 1st Mechanized Corps had at the present moment fewer than 100 tanks remaining.
Pskov and Ostrov were captured within weeks. On 2 August 1941, Colonel Limarenko, Chief of Staff of the 1st Mechanized Corps reported that the Corps possessed no
T-34 or
KV-1s. When sent into action, only 20 were delivered after combat began. The 1st Mechanized Corps was disbanded in August 1941, although the 1st Tank Division remained in 14th Army.
Second formation The Corps was formed a second time on the basis of the 27th Tank Corps on 8 September 1942 in Kalinin. It fought actively during the Second World War from 26 September—10 March 1943, from 9 July 1943—13 January 1944, from 7 June 1944—5 September 1944, and from 30 October 1944—9 May 1945. After the end of World War II, the Corps became part of the Group of Soviet Occupation Forces in Germany. ==Cold War==