The Ukrainian Insurgent Army (Ukrainska Povstanska Armiya -UPA) -- which was founded in 1942 and recognized the leadership of Bandera -- numbered about 200,000 men and women in the war. UPA and other Ukrainian guerilla groups, fought against the totalitarian armies of both Germany and Soviet Russia in the hope of winning and maintaining an independent Ukraine. A German document of November 25, 1941 (Nuremberg Trial O14-USSR) ordered: "It has been ascertained that the Bandera Movement is preparing a revolt in the Reichskommissariat which has as its ultimate aim the establishment of an independent Ukraine. All functionaries of the Bandera Movement must be arrested at once and, after thorough interrogration, are to be liquidated..." Although the German Army had control of the cities most of the forested and mountainous western and northern rural Ukraine was controlled by UPA. General Roman Shukhevich, who was the Commander-in-Chief of the UPA, and Chairman of the Ukrainian Supreme Liberation Council (UHVR) established 1944, kept the guerilla war going against the USSR and was killed in action against the USSR in 1950, five years after the war.

Early in the war, Moscow discovered that its troops were often sympathetic to the Ukrainian guerillas. Not only did the Soviet soldiers supply the guerillas with guns and ammunition they also often joined them. So Moscow later fought the Ukrainian nationalist guerillas only with special troops such as the NKVD and Soviet partisans.