The United States Air Force Security Forces (SF) are the ground combat force and military police service of the U.S. Air Force and U.S. Space Force. USAF Security Forces (SF) were formerly known as Military Police (MP), Air Police (AP), and Security Police (SP) at various points in its history. Due to its significant ground combat mission, Security Forces are often regarded as Air Force infantry within the Air Force and were formed on the premise of being the Air Force's "Marine Corps", in that they would provide security for the Air Force similar to how the Marines provide security for the Navy.