When Germany occupied Denmark in April 1940, ties were cut with Iceland which pursued a strict course of neutrality. However, in May 1940 British forces took de facto control of the country. American forces relieved the British a year later and remained there for the duration of the war.
With Germany threatening their colony of Greenland, the Danish envoy in Washington acting independently, requested the protection of the United States in May 1941. For the remainder of WWII the United States maintained extensive air and sea facilities in Greenland, as well as radio beacons, radio stations, weather stations, ports, depots, artillery posts, and search-and-rescue stations.