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,
Imperial Japanese Navy in World War II on the American perimeter. The Japanese continued to underestimate the number of American forces on the island, assuming that were that only 2,000 marines were on the island. However, the actual number was closer to 20,000, subsequently attacks launched by the Japanese on two successive nights on September 12–14, failed. Meanwhile, the Japanese did better in the struggle for control of the waters around Guadalcanal. On September 15, the submarine sank the carrier , leaving only a single American carrier, the , active in the Pacific at the time. However, as the Japanese possessed up to six operational carriers during