Soviet troops landed on Paramushir on August 18, 1945, during the Invasion of the Kuril Islands, and combat operations continued through August 23, ending with the surrender of the surviving members of the Japanese garrison. The Soviets forcibly deported the remaining Japanese civilian inhabitants and sent the prisoners of war to labor camps. Kashiwabara was renamed Severo-Kurilsk and the island annexed by the Soviet Union in 1946. Japan formally gave up sovereignty over the island under the terms of the San Francisco Peace Treaty of 1951.