SEOUL, Oct. 6 (UPI) -- North Korean leader Kim Jong Un visited the country's first 5,000-ton destroyer and called for bolstering naval power to "punish" threats to national sovereignty, state-run media reported Monday. Kim visited the Choe Hyon destroyer on Sunday with high-ranking party and government officials as part of his tour of a military hardware exhibition, the official Korean Central News Agency reported. Pyongyang launched the Choe Hyon at the Nampo Shipyard in April. The vessel is