The Soviets and the Poles distrusted each other and Soviet partisans in Poland often clashed with a Polish resistance increasingly united under the Home Army 's front . Stalin broke off Polish-Soviet relations on 25 April 1943 after the Germans revealed the Katyn massacre of Polish army officers , and Stalin refused to admit to ordering the killings and denounced the claims as German propaganda . Afterwards , Stalin created the Rudenko Commission , whose goal was to blame the Germans for the war crime at all costs . The Western alliance accepted Stalin 's words as truth in order to keep the Anti-Nazi alliance intact . On 26 October , the Polish government-in-exile issued instructions to the effect that , if diplomatic relations with the Soviet Union were not resumed before the Soviet entry into Poland , Home Army forces were to remain underground pending further decisions
Katyn massacre
Katyn massacre
Warsaw Uprising