In the early years of the war , following German invasion of the Soviet Union , many Polish and Soviet partisans saw Germans as the common enemy , and hostility between the two groups was limited . However , by mid-1943 , as the Soviets gained the upper hand and started to push German forces westwards , and following the breakdown of diplomatic relationship between Polish government in exile and the Soviet Union in the aftermath of the revelations about the Katyn massacre on June 22 , 1943 , Soviet partisans received orders to engage non-communist Polish partisans of Armia Krajowa , and the hostilities between the two groups escalated . On numerous occasions in the years 1943-1944 , Soviets would invite Polish partisans to talks , then disarm them and execute Polish partisan leaders
Katyn massacre
Katyn massacre
Soviet partisans