Third and fourth terms of the presidency of Franklin D. Roosevelt well-defended island of Iwo Jima, taking control of that island the following month. On April 1, the U.S. landed on Okinawa Island, the largest of the Ryukyu Islands. The Japanese allowed the Americans to land on the island before launching a fierce attack that included "kamikaze" suicide attacks by Japanese aircraft. Japanese forces on Okinawa held out until June 1945; U.S. forces suffered over 60,000 casualties during the operation. In late 1943, Roosevelt, Churchill, and Stalin agreed to meet to discuss strategy and post-war plans at the Tehran Conference, which marked Roosevelt's first face-to-face meeting with Stalin. At the conference,
Japanese colonial empire provided convenient provisioning locations for ships. During the 1930s, the Imperial Japanese Navy began construction of airfields, fortifications, ports, and other military projects on the South Pacific Mandate islands, viewing them as "unsinkable aircraft carriers" with a critical role to play in the defense of the Japanese home islands against potential invasion by the United States. The islands became important staging grounds for Japanese air and naval offensives during the Pacific War, but were lost to American military action between 1943 and 1945. The League of Nations mandate was formally revoked by the United Nations on July 18, 1947 pusuant