A military and displacement operation by the Communist-controlled Polish Army (WP) and Militia (MO) against the Ukrainian Liberation Army (UPA), the Organization of Ukrainian Nationalists (OUN) and civilians accused of co-operation with the partisans. More than 140,000 Ukrainians were deported from southeast Poland and resettled forcibly in the western territories gained from Germany. Most of Ukrainian partisan troops were destroyed too. Communist-controlled government confiscated possessions of displaced people as well as the property of Greek Orthodox Church and Ukrainian organizations.
Action lasted from April until July 1947.