SEOUL: A nuclear-powered US aircraft carrier, the Theodore Roosevelt, arrived in the South Korean port city of Busan on Saturday to take part in joint military exercises later this month with the host nation and Japan, naval officials said. The leaders of the three countries agreed at a summit last August to hold annual military training drills as they sought to project unity in the face of China’s growing power and nuclear threats from North Korea.This month’s drills, called “Freedom Edge”, will include maritime, anti-submarine warfare exercises and air defence.