Following the German invasion of the Soviet Union on 22 June 1941, Petrov's corps fought in the Battle of Białystok–Minsk. The corps was initially stationed in the rear but was moved forward to Baranovichi to stop the German advance, after the initial German breakthrough. On 26 June it fought defensive battles around Baranovichi, Stowbtsy, and Minsk, but the XLVII Army Corps (Motorized) managed to penetrate the corps' defenses. Outnumbered, the 17th Mechanized Corps was unable to offer much resistance to the attack and its remnants retreated eastwards to the Berezina, where they linked up with other Soviet units. It suffered heavy losses in the fighting and on 5 July became part of the 21st Army after being ordered to move to Babruysk on the previous day. By 7 July the corps had no armored vehicles left and later in the month the corps was withdrawn to the Sukhinichi area with the 4th Army. It was then converted into the 147th Tank Brigade on 1 August.