Regional tensions have risen markedly since the reclusive North conducted its sixth, and by far its most powerful, nuclear test on September 3.
The 15-member Security Council voted unanimously on a US-drafted resolution and a new round of sanctions on Tuesday in response, banning North Korea's textile exports that are the second largest only to coal and mineral, and capping fuel supplies.
The North reacted to the latest action by the Security Council, which had the backing of veto-holding China and Russia, by reiterating threats to destroy the United States, Japan and South Korea.
"Let's reduce the US mainland into ashes and darkness. Let's vent our spite with mobilisation of all retaliation means which have been prepared till now," the statement said.
The North's latest threats also singled out Japan for "dancing to the tune" of the US, saying it should never be pardoned for not offering a sincere apology for its "never-to-be-condoned crimes against our people", an apparent reference to Japan's wartime aggression.
It also referred to South Korea as "traitors and dogs" of the US.
Japan criticised the North's statement harshly.
"This announcement is extremely provocative and egregious. It is something that markedly heightens regional tension and is absolutely unacceptable," Japanese Chief Cabinet Secretary Yoshihide Suga said.
North Korea had already categorically rejected the Security Council resolution imposing sanctions over its latest test, vowing to press ahead with its nuclear and missile programmes in defiance of international pressure.
A tougher initial US draft of Tuesday's resolution was weakened to win the support of China and Russia. Significantly, it stopped short of imposing a full embargo on oil exports to North Korea, most of which come from China.
The latest sanctions also make it illegal for foreign firms to form commercial joint ventures with North Korean entities.
US President Donald Trump has vowed that North Korea will never be allowed to threaten the US with a nuclear-tipped missile, but has also asked China to do more to rein in its isolated neighbour. China in turn favours an international response to the problem.
The North accuses the US, which has 28,500 troops in South Korea, of planning to invade and regularly threatens to destroy it and its Asian allies.
The US and South Korea are technically still at war with North Korea because the 1950-53 Korean conflict ended with a truce and not a peace treaty.
Test 'bigger than first thought'
North Korea's nuclear test this month may have been stronger than first reported, equivalent to 17 times the strength of the bomb that destroyed Hiroshima, according to analysis by a US monitoring thinktank.
North Korea's September 3 nuclear test, its sixth and biggest, showed how much progress the country has made on its nuclear programme.
Estimates of the bomb's yield, or the amount of energy released by the blast, have ranged from South Korea's 50 kilotons to Japan's 160 kilotons, although some analysts have said the 6.3 magnitude of the earthquake caused by the detonation could put it into the "hundreds of kilotons".
This would put it into the realm of thermonuclear weapons, supporting North Korea's claim that it had tested a hydrogen bomb.
In comparison, the bomb detonated over Hiroshima in 1945 released about 15 kilotons of energy.
The new analysis by 38 North, run by the US-Korea Institute at the Johns Hopkins School of Advanced International Studies, found North Korea's test may have been much stronger.
Updated seismic data showed the magnitude of the resulting earthquake was greater than initial estimates - between 6.1 and 6.3. That means the yield of the latest test was roughly 250 kilotons, reported 38 North.
In other words, the test may have been almost 17 times stronger than the bomb detonated over Hiroshima. Washington Post
