Republic of Korea Army divisions are major tactical formations led by general officers. There are currently 39 Army and two Marine divisions. Of the 41 Army divisions, six are mechanized infantry divisions (combined arms formations centered around tanks, IFVs, APCs, and SPGs), 16 are infantry divisions (motorized divisions with various levels of mechanization), 12 are "Homeland Infantry Divisions" (향토보병사단, infantry divisions kept at a 40–50% manpower level, to be reinforced during national emergencies) and seven "Reserve Infantry Divisions" (동원보병사단, infantry divisions kept at 10–20% manpower level, to be reinforced during national emergencies). There are two Marine divisions organized similarly to their American counterparts. Though similarly formed, the 1st ROK Marine Division is specialized to perform amphibious landing operations while the 2nd ROK Marine Division performs more security operations and mans a sector of the DMZ facing the North Korean border.