There was no organise opposition to the regime within the USSR during the war which disappointed Hitler.
Millions of Soviet citizens welcomed the invading German armies as liberators from the harsh nature of Stalinist rule.
Many of these came from the national minorities in the west of the USSR such as the Baltic States, Ukraine and Belarus.
Some became enthusiastic volunteers for the German Army.
Cossacks provided 250,000 troops to the Germans.
The "Russian Liberation Movement" formed in Ukraine had up to 50,000 men fighting for the Germans as part of the Waffen SS.
Some prisoners and deserters joined the German forces.
As Slavs, they were considered inferior to Aryan German soldiers and were not often given combat duties.
Labelled as Hilfwillige ("those willing to help"), they were given jobs such as drivers, cooks, hospital attendants and messengers.
Russian prisoners who were forced to carry out menial tasks to support the German Army such as cleaning kitchens and toilets or looking after the stables.
Anyone suspected of collaborating with the enemy suffered the harshest of treatments if captured by the Red Army or if identified and arrested in the post-war years.
The Cossacks were virtually wiped out for supporting the German Army.