The German-Soviet Non Aggression Pact signed in August 1939 allowed Hitler to proceed with the invasion of Poland on September 1, 1939; igniting war throughout Europe. The British and French had pledged support to Poland and after Germany invaded both countries declared war on Germany on September 3, 1939. The German army invaded from three directions and unleashed a new type of warfare: Blitzkrieg. German forces reached Warsaw on September 8th, the Soviets invaded Eastern Poland on September 17, Warsaw surrendered on September 28th and the war in Poland was virtually over by the 30th. Germany now turned its forces to Western Europe.