In 1939 Denmark signed a 10-year non-aggression pact with Nazi Germany but Germany invaded Denmark on 9 April 1940 and the Danish government quickly surrendered. World War II in Denmark was characterised by economic co-operation with Germany until 1943, when the Danish government refused further co-operation and its navy scuttled most of its ships and sent many of its officers to Sweden, which was neutral. The Danish resistance performed a rescue operation that managed to evacuate several thousand Jews and their families to safety in Sweden before the Germans could send them to death camps. Some Danes supported Nazism by joining the Danish Nazi Party or volunteering to fight with Germany as part of the Frikorps Danmark. Iceland severed ties with Denmark and became an independent republic in 1944; Germany surrendered in May 1945. In 1948, the Faroe Islands gained home rule. In 1949, Denmark became a founding member of NATO.