The North Korean leader, Kim Jong-un, has ordered his country to be ready to use nuclear weapons "at any time" in the face of a growing threat from enemies, its official media said on Friday, Reuters reported.
Kim, who was supervising the exercise of newly developed multiple rocket launchers, also said his country should turn its military posture to a "pre-emptive basis" because enemies were threatening the state's survival, its KCNA news agency said.
The apparent warning to the west comes only days after North Korea fired a volley of short-range missiles into the sea off its east coast.
This followed the UN security council's unanimous approval of the toughest sanctions against the regime in two decades over its nuclear and rocket tests.
North Korea has previously carried out live firing near or across its borders when facing international condemnation.