North Korea's leader Kim Jong-un has ordered his country's nuclear weapons to be readied for use at a moment's notice according to the Korean Central News Agency (KCNA).
He also said Pyongyang will prepare its military to carry out 'pre-emptive attacks because of growing threats from the country's enemies'.
"The only way for defending the sovereignty of our nation and its right to existence under the present extreme situation is to bolster up nuclear force both in quality and quantity," KCNA said.
It stressed "the need to get the nuclear warheads deployed for national defence always on standby so as to be fired any moment".
The threat comes after the UN voted to impose its toughest sanctions to date over the North's recent nuclear test and long-range rocket launch.
North Korean state media had warned that the imposition of new sanctions would be a "grave provocation" that shows "extreme" US hostility against the country.
It said the sanctions would not result in the country's collapse or prevent it from launching more rockets.
North Korea reportedly has a handful of crude atomic bombs, but most experts doubt whether it is technologically able to shrink a warhead and mount it on a missile.