North Korean leader Kim Jong Un has vowed to use nuclear weapons if his country’s sovereignty was threatened, Pyongyang’s state media reported on Friday. North Korea’s military “would use without hesitation all the offensive forces it possesses, including nuclear weapons,” Kim said during a visit to an army training base on Wednesday, state-controlled KCNA news agency reported. “If such a situation comes, the permanent existence of Seoul and the Republic of Korea would be impossible,” he said, using South Korea’s official name. On Tuesday, South Korean President Yoon Suk Yeol warned North Kore…