North Korea has issued new threats against its perceived enemies by threatening to use nuclear bombs to "sink" Japan and reduce the United States to "ashes and darkness".

The North's official KCNA news agency on Thursday (14 September) said that the threat comes in response to the UN Security Council (UNSC) adopting tougher sanctions against the Kim Jong-un regime. The UNSC took the step as Pyongyang conducted its sixth and largest nuclear test earlier this month.

"The four islands of the archipelago should be sunken into the sea by the nuclear bomb of Juche. Japan is no longer needed to exist near us," the Korea Asia-Pacific Peace Committee said in a statement.

The committee is an affiliate of the North's ruling Workers' Party and handles the country's external ties and propaganda.

Juche "is the North Korea's ruling ideology that mixes Marxism and an extreme form of go-it-alone nationalism preached by state founder Kim Il-sung, the grandfather of the current leader, Kim Jong-un," the Reuters news agency reported.

The committee also called for the breakup of the 15-member UNSC and labelled it "a tool of evil". It also said the council is made of "money-bribed" countries that act according to the orders directed by the US.

The latest round of tough sanctions against North Korea had the support of China and Russia, who have favoured Pyongyang at several instances in the past despite mounting pressure from the US.

In retribution, the North's committee threatened to destroy the US and its regional allies 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," KCNA cited the committee as saying.

North Korea  nuke test celebration
North Korea has threatened to destroy the US and its regional allies Japan and South Korea over the recent UN Security Council sanctions KCNA via Reuters

Pyongyang's latest threats also took aim at Tokyo for "dancing to the tune" of Washington, while labelling South Korea as "traitors and dogs" of the US.

It said Tokyo should never be forgiven for not offering a sincere apology for its "never-to-be-condoned crimes against our people" in an apparent reference to Japan's wartime aggression.

Japan sharply criticised and condemned the latest threat by the North saying that it is only further likely to spike tensions in the Korean peninsula.

"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 told a regular news conference on Thursday, 14 September.

On 11 September, the UNSC unanimously agreed to step up economic sanctions imposing a ban on the North's textile exports and capping crude oil imports. The US-drafted resolution also called for a cap on the number of North Korean workers allowed overseas as they earn wages which contribute to the reclusive regime.

North Korea propaganda video on US Capitol
A North Korean propaganda site had released a video in April in which it said its military will destroy the US if threatened

This is not the first time North Korea has threatened to strike the US and its allies. Soon after the sanctions were imposed on the regime in August, Pyongyang warned it would turn the US turn into a "sea of fire", while promising "more gift packages" to the traditional enemy.

On 13 September, Pyongyang vowed to redouble its nuclear and weapons programme efforts to protect its sovereignty as it rejected the latest UN sanctions. The isolated nation also warned the US would suffer the "greatest pain" for engineering harsh sanctions against it.

The North is "ready to use a form of ultimate means," as the US has "fired up political, economic, and military confrontation," North Korea's ambassador to the UN, Han Tae-song said in his first reaction to the sanctions.