In the beginning of the Second World War , the area was annexed by the Soviet Union and attached to Ukraine , which at that time was a republic of the Soviet Union . According to the Yalta Conference decisions , while the Polish population of Eastern Galicia was resettled to Poland , the borders of which were shifted westwards , the region itself remained within the Soviet Ukraine after the war and currently forms the westernmost part of now independent Ukraine
Yalta Conference
Yalta Conference
Polish–Ukrainian War