South Korea and the United States on Saturday kicked off a joint naval exercise in the Sea of Japan involving three U.S. aircraft carriers amid heightened tensions on the Korean Peninsula.South Korea's Joint Chiefs of Staff said that the four-day strike force exercise is "aimed at enhancing deterrence against North Korea's nuclear and missile threats."According to the U.S. Navy, it is the first three-carrier exercise in the Western Pacific since 2007.The three flattops are the USS Ronald Reagan, Nimitz and Theodore Roosevelt. They will successively enter the exercise area in international w…READ FULL ARTICLE