operational control of units deployed to his MZ area of responsibility. Force strength varies greatly from a single infantry battalion in the 3rd Military Zone covering the relatively peaceful area of Baja California Sur to over 10 infantry battalions, separate infantry companies and motorized cavalry regiments plus additional conventional and SF units on rotation in the 9th Military Zone covering the state of Sinaloa, where government troops are fighting the eponymous drug cartel. The Mexican Air Force, which is an independent military service under the SEDENA, has its own territorial organization, separate from that of the Mexican Army. It has four air force regions: Northwest (Región Aérea del Noroeste, HQ in Hermosillo, Sonora), Northeast (Región Aérea del Noreste, HQ in Chihuahua, Chihuahua) Central (Región Aérea del Centro, HQ at Santa Lucía AFB, Estado de México) and the Southeast Air Force Region (Región Aérea del Sureste, HQ at Tuxtla Gutiérrez, Chiapas). Each new commanding officer of an air force region enters the appointment as a Wing General Pilot-Aviator of the Air Force Staff (General de Ala Piloto Aviador Diplomado de Estado Mayor Aéreo) - a two-star general and midway through his term he is promoted to a Division General Pilot-Aviator of the Air Force Staff (General de División Piloto Aviador Diplomado de Estado Mayor Aéreo) - a three-star general. A similar territorial organization is also implemented in the Mexican Navy with Naval Regions and Naval Zones as counterparts to the army territorial organization. Tactical units Separate from the military regions and zones are an increasing number of brigades and some independent regiments and infantry battalions. These brigades are grouped into four corps: 1st Army Corps (1er Cuerpo de Ejército (ICE)) - based in and around Mexico City and its metropolitan area. The corps consists of the 1st Armored Brigade, the 1st, 2nd and 3rd Separate Infantry Brigades and the army's sole 1st Combat Engineer Brigade. Additionally 3 armored brigades (2nd, 3rd and 4th) and 3 light infantry brigades (4th, 5th and 6th) separate from the 1st Army Corps, but based in the same area close to the capital complete the Mexican Army's maneuver formations. Special Forces Corps (Cuerpo de Fuerzas Especiales) - HQ, training center and the bulk of special forces battalions are based in Temamatla in the State of Mexico. The corps has 3 SF brigades headquartered in Puebla, Puebla (1st), Tijuana, Baja California (2nd) and Ixtepec, Oaxaca (3rd) and