Polish-Lithuanian relations during the interbellum period were strained since both sides had laid claim to the Vilnius region. During the Second World War these tensions were exacerbated due to conflicts between the Lithuanian pro-German administration and military units, and the anti-Nazi Polish resistance, as well as the discrimination against Poles by the independent Lithuanian state between 1939 and 1940. On 20 June 1944 members of the Polish resistance killed four members of the Lithuanian police, and wounded several others in the village of Glitiškės (Glinciszki); in retaliation the Lithuanian police killed thirty-six Polish villagers (the Glinciszki massacre). After hearing of this, as well as other information about intensified pacification actions by the Lithuanian forces, the Arm