After the Polish Defensive War of 1939 and the outbreak of World War II the town was briefly occupied by Nazi Germany, after which it was transferred to the Soviet Union. During the Soviet occupation many of the local inhabitants were sent to the Gulag camps; there was also a notable NKVD prison located in the town. In 1941, after the end of the Nazi-Soviet Alliance and the outbreak of the Russo-German War, the town was again occupied by Germany and attached to the so-called Distrikt Galizien of the General Government. Before World War II Brzezany's Jewish population was about 4,000, while after 1939 this population tripled with an additional 8,000 Jews, refugees from eastern German-occupied territories. After the Soviets left in July 1942 (after murdering many Ukrainian civilians), the Ukrainians launched a pogrom, murdering dozens of the town's Jews, looting and injuring Jews. In December 1941, approximately 1,000 Jews were killed in the Lityatyn forest. On 12 June 1943 the Nazis murdered almost all the Jews from the Brzezany ghetto and work camp at the local cemetery; only a few escaped. Between 1942 and the end of the war there was heavy partisan activity in the area, mostly by local branches of the Armia Krajowa.