North Korean leader Kim Jong Un supervised the exercise of newly developed multiple rocket launchers and 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.
Kim also said his country should turn its military posture to a "pre-emptive basis" because enemies are threatening the state's survival, its KCNA news agency said.
Kim said North Korea should "bolster up (its) nuclear force both in quality and quantity" and stressed "the need to get the nuclear warheads deployed for national defense always on standby so as to be fired any moment," KCNA quoted him as saying.
"Now is the time for us to convert our mode of military counteraction toward the enemies into an preemptive attack one in every aspect."
It comes after North Korea fired several short-range projectiles into the sea on Thursday, hours after the United Nations' Security Council voted to impose tough new sanctions on the isolated state and South Korean President Park Geun-hye vowed to "end tyranny" by the North's leader.
The firing escalated tensions on the Korean peninsula, which have been high since the North's January nuclear test and February long-range rocket launch, and set the South's military on a heightened alert.
South Korea's Defence Ministry said it was trying to determine if the projectiles, launched at 10 a.m. (0100 GMT) from the North's east coast, were short-range missiles or artillery fire.
Park has been tough in her response to the North's recent actions, moving from her earlier self-described "trustpolitik" approach, and on Thursday welcomed the move by the Security Council and repeated her call for the North to change its behavior.
"We will cooperate with the world to make the North Korean regime abandon its reckless nuclear development and end tyranny that oppresses freedom and human rights of our brethren in the North," Park said at a Christian prayer meeting on Thursday.
More to come.