After the Luzon landings, the force stepped up its sorties into the South and East China Seas. It struck repeatedly at enemy installations from Saigon to the Ryukyus and frequently sailed northeast to raid the industrial heart of the Japanese Islands. On 19–21 February 1945 they supported the invasion of Iwo Jima and then steamed west again towards Tokyo. By 1 March they had begun an intensified raiding campaign against the Ryukyus and Japan, again preparing the way for an invasion force.