Although the majority of Ukrainians fought in or alongside the Red Army and Soviet resistance, in Western Ukraine an independent Ukrainian Insurgent Army movement arose (UPA, 1942). Created as armed forces of the underground (Organization of Ukrainian Nationalists, OUN) which had developed in interwar Poland as a reactionary nationalist organization. During the interwar period, the Polish government's policies towards the Ukrainian minority were initially very accommodating; however, by the late 1930s they became increasingly harsh due to civil unrest. Both organizations, OUN and UPA supported the goal of an independent Ukrainian state on the territory with a Ukrainian ethnic majority. Although this brought conflict with Nazi Germany, at times the Melnyk wing of the OUN allied with the Nazi forces. Beginning in mid-1943 and lasting until the end of the war, UPA carried out massacres of ethnic Poles in the Volhynia and Eastern Galicia regions, killing around 100,000 Polish civilians, which brought reprisals. The organized massacres were an attempt by OUN to create a homogeneous Ukrainian state without a Polish minority living within its borders, and to prevent the post-war Polish state from asserting its sovereignty over areas that had been part of prewar Poland. After the war, the UPA continued to fight the USSR until the 1950s. At the same time, the Ukrainian Liberation Army, another nationalist movement, fought alongside the Nazis.