Following the Luzon assault, the carrier force's sorties into the South and East China Seas were stepped up. The ships and planes repeatedly blasted installations from Saigon to the Ryukyus and frequently sailed north to raid Japan's industrial heart. On 19–21 February 1945, the force supported the assault in Iwo Jima, then steamed west again to pound the Tokyo plain. By mid-March, an intensified raiding campaign against the Ryukyus and Japan was well underway, preparing the way for an invasion force.