The Republic of China Air Force, retroactively known by its historical name the Chinese Air Force and unofficially referred to as the Taiwanese Air Force, is the military aviation branch of the Republic of China Armed Forces, currently based in Taiwan. The ROCAF was founded in 1920 by the Kuomintang. While its historical name is sometimes used especially in domestic circles, it is not used as often internationally due to the current ambiguous political status of Taiwan and to avoid confusion with the People's Liberation Army Air Force of the People's Republic of China (PRC). Its primary mission is the defense of the airspace over and around the Taiwan area. Priorities of the ROCAF include the development of long range reconnaissance and surveillance networks, integrating C4ISTAR systems to increase battle effectiveness, procuring counterstrike weapons, next generation fighters, and hardening airfields and other facilities to survive a surprise attack. In May 2005, the Ministry of National Defense indicated its intention to transfer command of all defensive missile systems to the ROCAF, while future offensive missiles would be placed under a newly formed missile command. As of 2006, all medium and long range SAM units were transferred from ROC Army's Missile Command to ROCAF, while ROCAF's airbase security units were transferred to ROC Army Military Police. However, it was revealed that in January 2011, five years of problems of integrating those long range ex-ROC Army SAM units into ROCAF has forced ROCAF high command to return those units back to ROC Army's Missile Command. Missile Command is now directly under Defense Ministry's GHQ control. In July 2010, former United States Air Force deputy under secretary for international affairs, Bruce Lemkin, said that Taiwan's ability to defend its airspace had degraded due to its aging fighters and that the sale of new US fighter aircraft to Taiwan was an urgent priority. However, the ROC Air Force has trouble getting fighter planes from abroad due to mainland China's attempts to suppress fighter sales from any country. The People's Republic of China has called the F-16 fighter or any foreign fighter sales a "red line". It is believed that mainland China plans to eliminate the ROC Air Force by preventing any sale of new aircraft whilst gradually wearing its ageing fighters into an inoperable state as they have to frequently intercept PLAAF aircraft who perform almost daily approaches to ROC airspace. According to the former