Before and during Operation Barbarossa, the invasion of the Soviet Union, German troops were indoctrinated with anti-Bolshevik, anti-Semitic and anti-Slavic propaganda.[13] Following the invasion, Wehrmacht officers told their soldiers to target people who were described as "Jewish Bolshevik subhumans", the "Mongol hordes", the "Asiatic flood" and the "Red beast".[14] Many German troops viewed the war in Nazi racialist terms and regarded their Soviet enemies as sub-human.[15] In a speech to 4th Panzer Group, General Erich Hoepner echoed the Nazi racial plans by claiming the war against the Soviet Union was "an essential part of the German people's struggle for existence", and that "the struggle must aim at the annihilation of today's Russia and must therefore be waged with unparalleled harshness."[16]