North Korea conducted a firepower strike drill involving 600-millimeter ultra-precision multiple rocket launchers, attended by leader Kim Jong-un, state media reported Sunday. "A long-range artillery sub-unit of the Korean People's Army in the western area conducted a firepower strike drill" the previous day, involving 12 "600 mm-calibre ultra-precision multiple rocket launchers and two artillery companies," the Korean Central News Agency said. The previous day, South Korea's military detected a