The Philippines was the bloodiest theater of the war for the invading empire, with at least 498,600 Japanese troops killed in fighting the combined Filipino resistance and American soldiers, a larger number of casualties compared to the second-placed theater, the entirety of China, which caused the Japanese about 455,700 casualties. The occupation of the Philippines by Japan ended at the war's conclusion. At the eve of the liberation of the Philippines, the Allied forces and the Japanese Empire waged the largest naval battle in history, by gross tonnage in the Battle of Leyte Gulf. The American army had been fighting the Philippines Campaign since October 1944, when MacArthur's Sixth United States Army landed on Leyte. Landings in other parts of the country had followed, and the Allies, with the Philippine Commonwealth troops, pushed toward Manila. However, fighting continued until Japan's formal surrender on September 2, 1945. Approximately 10,000 U.S. soldiers were missing in action in the Philippines when the war ended, more than in any other country in the Pacific or European Theaters. The Philippines suffered great loss of life and tremendous physical destruction, especially during the Battle of Manila. An estimated 1 million Filipinos had been killed, a large portion during the final months of the war, and Manila had been extensively damaged.