For the Nazis, the invasion and occupation of Poland was a laboratory of extermination for the Jews of Eastern Europe. From the first days of the war, a surge of violence accompanied the German troops: lootings, rapes, massacres of the Polish and Jewish intelligentsia. In November 1939, one of the first mass shootings of Jews took place in Ostrów Mazowiecka: about 500 men, women and children were executed in mass graves outside of the town.
At the same time as Operation Barbarossa, a number of pogroms broke out, under the Nazi impetus, on formerly Polish territory and retaken by the Soviet Union. Scenes of humiliation and killings multiplied in the streets of Lvov, Bialystok, Kaunas—but also in Iasi, under the supervision of the Romanian authorities. Nazi propaganda, relaying these bloody events, pointed their finger at the enemy to be finished off—the Jewish-Bolshevik. Behind army lines, SS mobile units and security police, under the orders of Himmler and Heydrich, the Einsatzgruppen had its mission, outside of their tasks of intelligence, to eliminate all potential opponents—communists, Komsomols, Jews, Roma and Sinti. The first victims of these troops were typically men, while the rest of the Jewish population in the towns and villages were gathered in ghettos where hunger, fear and epidemic reigned. But, beginning in August 1941, Jewish women and children were no longer spared. On August 27, 28 and 29, 23,600 Jews—men, women and children—mostly originating from Transcarpathian Hungary, were exterminated near the town of Kamenets-Podolski. In Kiev, on September 29-30, 1941, the entire Jewish population of the town was shot at the edge of the Babi Yar ravine. Between Christmas and the New Year of 1941-1942, about 50,000 Jews from the town of Odessa and from the region were killed in Bogdanovka.
Despite the set up of extermination camps, the shootings in the East continued, in Poland as well as in the occupied Soviet territories, up to Leningrad and Stalingrad. In September 1942, 10,000 Jews, mainly refugees trapped by the German advance, were executed in Mineralnyie-Vody, at the door of the Caucuses. In November 1943, the Erntefest Aktion triggered a series of liquidations of ghettos in the region of Lublin, Poland. In spring of 1944, they continued to shoot hundreds of Jews in Kaunas, Lithuania.
The map below shows the movements of the Einsatzgruppen units A, B, C and D in Eastern Europe and the resepective number of victims that each unit killed between 1941-1942. It is important to note that this map shows only a group of the victims of the Jews in the Soviet Union as mass shootings continued from 1941-1944 and were also carried out by other Nazi units, including police batallions, the Waffen-SS, the Wehrmacht, and local auxiliaries.