South Korean and US troops began five days of naval drills on Monday after North Korea renewed its threat to fire missiles near the American territory of Guam, AP said. The maneuvers involve fighter jets, helicopters, and 40 naval ships and submarines from the allies, including the aircraft carrier USS ‘Ronald Reagan’, South Korea’s Navy said. The drills are aimed at “practicing how to respond to a potential naval provocation by North Korea” and improving the allies’ combined operational capability. The drills are expected to include live-fire exercises by naval ships, as well as aircraft and anti-submarine training.