The 604th Special Operations Squadron is an inactive United States Air Force squadron It was last active at Bien Hoa Air Base, Vietnam, where it was inactivated in September 1970. The squadron was first activated in the spring of 1944 as the 4th Fighter Reconnaissance Squadron, although it was soon redesignated the 4th Fighter Squadron (Commando). It moved to the Pacific in the fall of 1944 and earned a Philippine Republic Presidential Unit Citation for combat in the Philippines. After the surrender of Japan, it served in the occupation forces until being inactivated in March 1946.