What was the role of the partisan and underground movement during the war?

Partisans and underground fighters fought against the Germans who occupied the territory of the USSR. It had a clear centralized organization and command. The partisans disrupted the supply of food and weapons to the German troops, participated in reconnaissance. Also, some detachments were engaged in propaganda, since the people needed to believe in a strong state. As a result, the partisans became a significant force that was able to ensure victory in the Second World War.