- Video report by ITV News China Correspondent Debi Edward
North Korea has threatened "thousands-fold" revenge against the US over the latest set of sanctions imposed on Pyongyang.
The North issued the threat two days after the UN passed tougher new sanctions targeting the secretive state in a bid to curb its nuclear weapons programme.
Meanwhile, the US and South Korea have reaffirmed the "grave and growing" threat North Korea poses to countries around the world.
Donald Trump and South Korean president Moon Jae-in spoke of increasing concern around Pyongyang's nuclear ambitions in a telephone conversation on Sunday.
The two leaders welcomed the latest punitive sanctions, which were introduced with the backing of 15 votes to 0, including those of Russia and China.
But while Trump and Moon praised the move, North Korea described the sanctions as part of a "heinous US plot to isolate and stifle" the country.
In their conversation, presidents Trump and Moon discussed how the recent launch of an intercontinental ballistic missile by the North emphasised its "direct" threat to the US, South Korea and Japan.
New sanctions passed by the UN in response to the development included the banning of £770 million worth of exports out of North Korea.
The resolution also banned countries from giving any additional permits to North Korean workers - a crucial source of foreign currency for the regime.
On Sunday, the White House said the US was committed to fully implementing all relevant resolutions and urged the international community to do so as well.
China also urged North Korea to abide by UN resolutions and stop provoking "the international community's goodwill" with missile launches and nuclear tests.
But North Korea has criticised the sanctions, threatening "thousands-fold revenge and "action of justice".
Meanwhile, US Secretary of State Rex Tillerson has described a halt in missile launches as the clearest sign of the North wanting to return to the negotiating table.
Tillerson, offering a clear indication of what preconditions to negotiations would be, said stopping the launches would be the "first and strongest signal".
He insisted that a halt in missile testing did not mean just for a few days or weeks.
And the Secretary of State said that the US had "other means of communication" open to North Korea if the country wished to express a desire to talk.