South Korea and the United States began a joint live-fire aerial exercise Monday, the South Korean Air Force said. The three-day exercise got under way earlier in the day over waters off South Korea's western coast, mobilizing some 60 military planes, including South Korea's F-35A, F-15K and KF-16 fighters and U.S. A-10 attack aircraft. On Monday, the F-35As fired AIM-120C medium-range air-to-air missiles, while the KF-16s dropped GBU-31 joint direct attack munitions that can penetrate 1-meter-thick reinforced concrete, the S. Korean Air Force said. The live-fire exercise is taking place in conjunction with the two countries' 11-day Ulchi Freedom Shield (UFS) exercise set to conclude Thursday. Source: Qatar News Agency