Einsatzgruppen
The Red Army retreated.  However, Heydrich thought there were Soviet guerrilla fighters still in the area and thought local Jews were helping them.  He ordered the Einsatzgruppen to encourage anti-Jewish pogroms in the newly occupied territories.  Pogroms (some of which the Einsatzgruppen started) broke out in Latvia, Lithuania, and Ukraine.p. 526 Within the first few weeks of Operation Barbarossa, 10,000 Jews were killed in 40 different pogroms.  By the end of 1941, about 60 pogroms had happened, killing up to 24,000 people.p. 526