 From February to September 1944, the German army detachment "Narwa" held back the Soviet Estonian Operation.After breaching the defence of II Army Corps across the Emajõgi river and clashing with the pro-independence Estonian troops, Soviet forces reoccupied mainland Estonia in September 1944.After the war, Estonia remained incorporated into the Soviet Union as the Estonian SSR until 1991, although the Atlantic Charter stated that no territorial arrangements would be made.