The Axis powers in World War II routinely invaded neutral countries on grounds of prevention and began the invasion of Poland in 1939 by claiming the Poles had attacked a border outpost first. In 1940, Germany invaded Denmark and Norway and argued that Britain might have used them as launching points for an attack or prevented supply of strategic materials to Germany. In the summer of 1941, Germany invaded the Soviet Union, inaugurating the bloody and brutal land war by claiming that a Judeo-Bolshevik conspiracy threatened the Reich. In late 1941, the Anglo-Soviet invasion of Iran was carried out to secure a supply corridor of petrol to the Soviet Union. Iranian Shah Rezā Shāh appealed to US President Franklin Roosevelt for help but was rebuffed on the grounds that "movements of conquest by Germany will continue and will extend beyond Europe to Asia, Africa, and even to the Americas, unless they are stopped by military force."