The US Navy conducted its first attacks against the Japanese home islands in mid-February 1945. This operation was undertaken primarily to destroy Japanese aircraft that could attack the US Navy and Marine Corps forces involved with the landing on Iwo Jima on 19 February, and was conducted by Task Force 58 (TF 58). This task force was the US Navy's main striking force in the Pacific, and comprised 11 fleet carriers, five light aircraft carriers and a powerful force of escorts. TF 58 approached Japan undetected, and attacked airfields and aircraft factories in the Tokyo region on 16 and 17 February. The American naval aviators claimed 341 "kills" against Japanese aircraft and the destruction of a further 160 on the ground for the loss of 60 aircraft in combat and 28 in accidents. Several ships were also attacked and sunk in Tokyo Bay. The actual Japanese aircraft losses in this operation are uncertain, however; the Imperial General Headquarters admitted losing 78 aircraft in dogfights and did not provide a figure for those destroyed on the ground. TF 58's ships were not attacked during this period in Japanese waters, and on 18 February sailed south to provide direct support to the landings on Iwo Jima. The Task Force attempted a second raid against the Tokyo area on 25 February, but this operation was frustrated by bad weather. The American ships sailed south, and attacked Okinawa from 1 March.