North Korean ruler Kim Jong Un has threatened the use of nuclear weapons in the event of military conflict with the United States and South Korea, according to remarks reported by state media on Thursday. “Our armed forces are thoroughly prepared to respond to any crisis,” Kim said. He added that North Korea’s nuclear deterrence forces were ready to mobilize “accurately and promptly” for their mission. Ahead of the start of joint summer military exercises by US and South Korean forces next month, Kim adopted a sharper tone than usual. South Korea faced total destruction, if it undertook “dange…