On August 28, the occupation of Japan led by the Supreme Commander for the Allied Powers began. The surrender ceremony was held on September 2, aboard the United States Navy battleship , at which officials from the Japanese government signed the Japanese Instrument of Surrender, thereby ending the hostilities. Allied civilians and military personnel alike celebrated V-J Day, the end of the war; however, isolated soldiers and personnel from Japan's far-flung forces throughout Asia and the Pacific refused to surrender for months and years afterwards, some even refusing into the 1970s. The role of the atomic bombings in Japan's unconditional surrender, and the ethics of the two attacks, is still debated. The state of war formally ended when the Treaty of San Francisco came into force on April 28, 1952. Four more years passed before Japan and the Soviet Union signed the Soviet–Japanese Joint Declaration of 1956, which formally brought an end to their state of war.