Taiwan will continue its efforts to buy F-16 C/D fighters despite reports that the U.S. administration has turned down the request. Taiwanese President Ma Ying-jeou said the aircraft are essential to the country\'s defenses, a report by Taiwan\'s Central News Agency said. Ma said the weapons are defensive in nature and under the Taiwan Relations Act the United States is obliged to provide Taiwan with the arms it needs to defend itself, the CNA report said. The purchases aren\'t meant to instigate an arms race with mainland China, with whom Taiwan has an improving relationship but are to replace aging equipment. \"We won\'t engage in an arms race with mainland China but we need to build up a strong and streamlined military force,\" Ma said during a promotion ceremony for senior military officers. Taiwan is pursuing \"three lines of defense\" in building national security, Ma said. Taipei is establishing rapport with Beijing as well as enhancing Taiwan\'s contribution to the international community and aligning defense policy with diplomacy. The CNA report said Taiwan has been seeking to buy the F-16 C/D fighters since 2006. The news that United States wouldn\'t sell Taiwan the requested 66 F-16 C/D aircraft was reported during last week\'s biennial Taipei Aerospace and Defense Technology Exhibition. An unnamed Taiwan Ministry of National Defense official said the United States had bowed to pressure from China to not sell the aircraft. \"We are so disappointed in the United States,\" he said. A U.S. Department of Defense delegation was in Taipei to offer an upgraded package for Taiwan\'s 146 F-16A/B aircraft, including an active electronically scanned array radar. \"The U.S. Pentagon is here explaining what is in the upgrade package,\" a U.S. defense industry source said at the exhibition. \"They are going to split the baby: no C/Ds, but the A/B upgrade is going forward.\" The Fighting Falcon F-16 first flew in 1974 and was operational with the U.S. Air Force in 1978. It was made by General Dynamics until 1993 when General Dynamics sold its aircraft manufacturing business to Lockheed Corp., which became part of Lockheed Martin after a 1995 merger with Martin Marietta. The prime user of the F-16 is the U.S. Air Force, although it no longer buys the aircraft. Upgraded versions are sold for export and around 25 countries operate the plane. Around 4,500 have been manufactured. Taiwan operates the most common variant -- the single-seat F-16A and two-seat F-16B. The F-16C/D variants first went into production in 1984 and have improved cockpit avionics and radar which added Raytheon\'s all-weather capability with beyond-visual-range AIM-7 and AIM-120 air-to-air missiles. A report by Defense News said the proposed upgrade would make Taiwan\'s F-16A/Bs \"among the most capable variants of the aircraft, perhaps second only to the APG-80 AESA-equipped F-16E/Fs flown by the United Arab Emirates.\" The upgrade would include either Northrop Grumman\'s Scalable Agile Beam Radar or the Raytheon Advanced Combat Radar to replace the planes\' current APG-66(V)3 radar. Defense News said either radar would be better than the Northrop APG-68(V)9 mechanical radar previously considered by Taiwan as an upgrade. Also, the new upgrade is intended to soften the blow of denying new planes to Taipei, a Lockheed Martin source said.