In 1943 the fragile relations between the Soviet Union and the Polish government-in-exile finally reached their breaking point when , on April 13 , the Germans announced via the Katyn Commission the discovery of the bodies of 20,000 Polish officers who had been murdered by the Soviets and buried in Katyn Forest , near Smolensk , Russia . Stalin claimed that the atrocity had been carried out by the Germans , while Nazi propaganda orchestrated by Joseph Goebbels successfully exploited the Katyn massacre to drive a wedge between Poland , the Western Allies and the Soviet Union . The Soviet Union , and subsequently Russia , did not acknowledge responsibility for this and similar massacres of Polish officers until the 1990s
bodies of 20,000 Polish officers
Katyn massacre
Władysław Sikorski