During the Japanese occupation of the Philippines an extensive Filipino guerrilla movement sprang up. In some cases the guerrilla units were led by escaped American officers (e.g., Wendell Fertig) and often included "paroled" Philippine Scout and Philippine Commonwealth Army soldiers, along with civilian members of the Philippine underground. As MacArthur's forces, supported by the guerrillas, liberated the Philippine Islands, the surviving Philippine Scouts stepped forward and rejoined the U.S. Army. The Filipino guerrillas joined them, and the U.S. Army set up new Philippine Scout units, reconstituting the old Philippine Division as the 12th Infantry Division. Subordinate units included the 43rd, 44th and 45th Infantry Regiments (PS); 23rd, 24th and 88th Field Artillery (PS) Battalions; 56th Engineer Battalion (PS) and the 57th Infantry Regiment (PS). The "New Scouts" actively participated in combat against the Japanese Army in north Luzon, served as military police to restore order and help locate pockets of escaped Japanese in the south, and served as occupation forces on Okinawa. As planning for the invasion of Japan progressed, the Philippine Scouts were included in the invasion forces, and were selected to become part of the occupying force once Japan was defeated.