North Korean general secretary Kim Jong-un supervised the military training of the North Korean military's tactical nuclear operation unit, the Korean Central News Agency said.
The broadcast said, "It is a military exercise to send a severe warning to enemies who have verified and determined war deterrence and nuclear counterattack capabilities."
He said the period lasted 15 days from September 25th to October 9th.
The military exercise was conducted at a time when large-scale naval forces of the Allied Forces, including US Navy aircraft carriers, Aegis destroyers, and nuclear-powered submarines, were conducting dangerous military exercises in the waters of the Korean peninsula.