Following the "Anschluss" of March 1938, during which Germany annexed Austria, Yugoslavia came to share its northwestern border with Germany and fell under increasing pressure as its neighbours aligned themselves with the Axis powers. In April 1939, Italy invaded and occupied Albania, thereby establishing a second land border with Yugoslavia. At the outbreak of World War II, the Royal Yugoslav Government declared its neutrality. Between September and November 1940, Hungary and Romania joined the Tripartite Pact, aligning themselves with the Axis, and Italy invaded Greece. Yugoslavia was by then almost completely surrounded by the Axis powers and their satellites, and its neutral stance toward the war became strained. In late February 1941, Bulgaria joined the Pact. The following day, German troops entered Bulgaria from Romania, closing the ring around Yugoslavia.