The NKVD prisoner massacres were a series of mass executions committed by the Soviet NKVD against prisoners in Eastern Europe, primarily Poland, Ukraine, the Baltic states, Bessarabia and other parts of the Soviet Union from which the Red Army was withdrawing after the German invasion in 1941 (see Operation Barbarossa). Estimates on the death toll vary, from nearly 9000 in all of Ukraine to 100,000,[2] with 10,000 in Western Ukraine alone.[3] Not all prisoners were murdered; some of them were abandoned or managed to escape because the retreating, panicked Soviet executioners logistically could not kill all of them.[4]