Between 1944 and 1945, Royal Air Force and United States Army Air Force bomber squadrons based in India repeatedly launched bombing raids on George Town, seeking to destroy naval and administrative facilities. The destruction of the Penang Secretariat building by the Allied bombardment caused the loss of a large part of the British and Japanese records concerning Penang Island, complicating post-war efforts to compile a comprehensive history of Penang. The Penang Strait was also mined as part of efforts to constrict Japanese shipping.