In September 1939, Nazi Germany and the Soviet Union each carved out their own spheres of influence in Poland and Eastern Europe via the Molotov–Ribbentrop Pact. The Soviets arrested 26,000 Polish officers in the eastern portion of Poland and in March 1940, after some deliberation, Stalin and five other members of the Politburo, Mikoyan included, signed an order for their execution as "nationalists and counterrevolutionaries". When Germany invaded the Soviet Union in June 1941, Mikoyan was placed in charge of organizing the transportation of food and supplies. His son Vladimir, a pilot in the Red Air Force, died in combat when his plane was shot down over Stalingrad. Mikoyan's main assignment throughout the war was supplying the Red Army with materials, food and other necessities.