In 1945, with the defeat of Japan in World War II, the Japanese administration in Karafuto ceased to function. The Japanese government formally abolished Karafuto Prefecture as a legal entity on June 1, 1949. In 1951, at the Treaty of San Francisco, Japan renounced its rights to Sakhalin, but did not formally acknowledge Soviet sovereignty over it. Since that time, no final peace treaty has been signed between Japan and Russia, and the status of the neighboring Kuril Islands remains disputed.