The announcement heralds a further escalation in activity close to the demarcation line separating the two Koreas, which had been rare in recent years until this year.
North Korea had already been installing landmines and barriers and creating wasteland along the heavily militarised border for months this year despite accidents, South Korea's military said in July.
The General Staff of the Korean People's Army said in a statement carried by KCNA that this was a response to war exercises that have been held in South Korea, which it called "the primary hostile state and invariable principal enemy", as well as frequent visits by U.S. strategic nuclear assets in the region.
