North Korea has said the United States will "suffer the greatest pain" over its role in bringing forth the latest sanctions on Pyongyang.
"The forthcoming measures ... will make the US suffer the greatest pain it ever experienced in its history," North Korea's Ambassador to the UN Han Tae Song said on Tuesday.
His comments come after the UN Security Council unanimously adopted a US-draft resolution imposing new sanctions on North Korea.
The resolution is a water-down version of the original US proposal, but it does ban North Korea from importing all natural gas liquids and condensates, as well as bans all textile exports and prohibits all countries from authorising new work permits for North Korean workers.
Han rejected the resolution as "illegal and unlawful" and said Washington was "fired up for political, economic, and military confrontation".
North Korea is "ready to use a form of ultimate means", Han said.
On Wednesday, Pyongyang also called the sanctions a "heinous provocation aimed at depriving the DPRK of its legitimate right for self-defence and completely suffocating its state and people through full-scale economic blockade," according to a statement from the state-run Korean Central News Agency (KCNA).
DPRK stands for North Korea's formal name, the Democratic People's Republic of Korea.
The statement also said that the sanctions "verify that the road [North Korea] chose to go down was absolutely right and to strengthen its resolve to follow this road at a faster pace without the slightest diversion until this right to finish is over".
Monday's text is the ninth resolution unanimously adopted by the 15-member council since 2006 over North Korea's ballistic missile and nuclear programme.
It came in response to Pyongyang's sixth and largest nuclear test on September 3, which it said was of an advanced hydrogen bomb.
'Very small step'
Meanwhile, US President Donald Trump said on Tuesday the latest UN sanctions on North Korea were only a very small step and nothing compared to what would have to happen to deal with the country's nuclear programme.
"We think it's just another very small step, not a big deal," Trump told reporters at the start of a meeting with Malaysian Prime Minister Najib Razak.
"I don't know if it has any impact, but certainly it was nice to get a 15-to-nothing vote, but those sanctions are nothing compared to what ultimately will have to happen," said Trump, who has vowed not to allow North Korea to develop a nuclear missile capable of hitting the United States.
The initial US proposal included an assets freeze on North Korean leader Kim Jong-un and a complete ban on countries selling oil to his government, but the measures were softened to appease China and Russia.
US Treasury Secretary Steven Mnuchin warned China that if it did not follow through on the new sanctions, the United States would "put additional sanctions on them and prevent them from accessing the US and international dollar system".
Another senior administration official told Reuters news agency that any such "secondary sanctions" on Chinese banks and other companies were on hold for now to give China time to show it was prepared to fully enforce the latest and previous rounds of sanctions.
Frustrated US lawmakers called at a House hearing on Tuesday for a "supercharged" response to North Korea's nuclear and missile tests and said Washington should act alone if necessary to stiffen sanctions on China firms and any country doing business with Pyongyang.
Ed Royce, the Republican chairman of the US House Foreign Affairs Committee, said time was running out and Chinese firms should be given "a choice between doing business with North Korea or the United States".
Assistant Treasury Secretary Marshall Billingslea acknowledged at the hearing he had not seen sufficient evidence past sanctions were effective, but defended the administration's strategy.
He called on anyone aware of efforts to enable North Korean trade to come forward before getting caught, warning: "We are closing in on North Korea's trade representatives."
Diplomatic talks
China's official Xinhua news agency said in a commentary that the Trump administration was making a mistake by rejecting diplomatic engagement with North Korea.
"The US needs to switch from isolation to communication in order to end an 'endless loop' on the Korean Peninsula, where "nuclear and missile tests trigger tougher sanctions and tougher sanctions invite further tests," it said.
China's UN Ambassador Liu Jieyi called on North Korea to "take seriously the expectations and will of the international community" that it halt its nuclear and ballistic missile development, and called on all parties to remain "cool-headed" and not stoke tensions.
Liu said relevant parties should resume negotiations "sooner rather than later".
To kick-start talks, China and Russia have proposed a dual suspension of North Korea's nuclear and ballistic missile testing, as well as US and South Korean military exercises.
The US has called the proposal insulting.
Source: Agencies