Japanese air attacks on the Mariana Islands 1945. While the attacks on Iwo Jima damaged the island's airfields, the Japanese managed to keep at least one of them operational at all times, and none were closed for more than a single day. The need to repair damage to the airfields forced the Japanese garrison on Iwo Jima to divert labor from building defensive positions, however. The combination of heavy losses over Saipan and damage to the airfields on Iwo Jima caused the Japanese to break off their attacks against the Marianas on 2 January. Few Japanese aircraft visited Iwo Jima starting in January, and due to their
South Pacific Mandate detachments. In order to capture the islands from Japan, the United States military employed a "leapfrogging" strategy which involved conducting amphibious assaults on selected Japanese island fortresses, subjecting some to air attack only and entirely skipping over others. This strategy caused the Japanese Empire to lose control of its Pacific possessions between 1943 and 1945. The League of Nations mandate was formally revoked by the United Nations on 18 July 1947 pursuant to Security Council Resolution 21, making the United States responsible for administration of the islands under the terms of a United Nations trusteeship agreement which established the Trust