South Korea has recently notified the United States of its intention to buy over 100 anti-tactical ballistic missiles (ATBMs) as part of efforts to boost its air and missile defense system, sources said Sunday. The sources said that the contact was confirmed by a recent report to the US Congress by the Defense Security Cooperation Agency, the overseas weapons sales branch of the US Defense Department, according to South Korea\'s (Yonhap) News Agency. The US agency said in the report that the South Korean government expressed its intention to purchase 112 anti-tactical ballistic missiles, their relevant gears, components and training aid, according to the sources. The price tag for the missiles and the complementary components is estimated to be US$404 million, according to the report. Under the purchase plan, which needs approval from the US Congress, US arms manufacturer Raytheon will deliver to South Korea the Guidance Enhanced Missiles-Tactical models, which are an upgraded version of Patriot Advanced Capability-2, the ATBM model currently in use by the South Korean military. South Korea is now planning to additionally purchase hundreds of ATBMs to build its own air defense system, called KAMD (the Korean Air and Missile Defense), amid increasing missile threats from North Korea.