SEOUL (Reuters) -North Korea has detained shipyard officials responsible for a recent major accident during the launch of a new warship, state media said on Sunday. The failed launch that crippled the 5,000-tonne warship was witnessed by leader Kim Jong Un who said the accident damaged the country's dignity and vowed to punish those found responsible. The mishap likely occurred in front of a large crowd at the northeastern port of Chongjin, increasing the public humiliation for Kim who tried to show off military might, experts say.