 Complete the following phrase:  In 1941, at the onset of Operation Barbarossa, the invasion of the Soviet Union, the main architect of the Holocaust, Reinhard Heydrich, issued his operational guidelines for the mass anti-Jewish actions carried out with the participation of local gentiles. Massacres of Polish Jews by the Ukrainian and Lithuanian auxiliary police battalions followed. Deadly pogroms were committed in over 30 locations across formerly Soviet-occupied parts of Poland, including in Brześć, Tarnopol, Białystok, Łuck, Lwów, Stanisławów, and in Wilno where the Jews were murdered along with the Poles in the Ponary massacre at a ratio of 3-to-1. National minorities routinely participated in pogroms led by OUN-UPA, YB, TDA and BKA. Local participation in the Nazi German cleansing operations included the 