In May 1940, during World War II, the United Kingdom initiated an invasion of politically neutral Iceland, fearing it would otherwise fall to the forces of Nazi Germany which had recently conquered Denmark. Iceland's indigenous population was generally opposed to the British occupation, instead preferring troops of the United States, which was neutral at that phase in the war. Iceland signed a defense agreement with the United States in which United States troops would be stationed on the island nation. The U.S. Marine Corps hastily assembled the 1st Provisional Marine Brigade in Charleston, South Carolina, to move to Iceland as part of the agreement. The brigade was first activated on 14 July 1941. Its elements were taken from the 2nd Marine Division, which was training at Marine Corps Base San Diego and Camp Elliott, both in San Diego, California. This brought the force up to a strength of 4,095 men. They were the first of 28,000 men occupying Iceland under Major General Holland M. Smith and his 1st Marine Division. While the 1st Marine Division was building its forces, though, the Provisional Brigade would hold Iceland. However, priorities soon changed and the 1st Marine Division was moved elsewhere. The 1st Provisional Marine Brigade was instead joined by units of the United States Army.