The US envoy to the UN has urged the Security Council to take the “strongest possible measures” against North Korea after its latest nuclear test.
“The time has come to exhaust all diplomatic means before it is too late,” Nikki Haley told an emergency meeting of the council in New York.
She also warned countries which did business with the North that they were aiding their nuclear ambitions.
Reports suggest the North is preparing new test missile launches.
Ms Haley said North Korean leader Kim Jong-un had shown through his actions that he was “begging for war”.
“War is never something the United States wants,” she said. “We don’t want it now but our country’s patience is not unlimited.”
North Korea is believed to have tested a nuclear bomb underground on Sunday. Estimates of its power range from 50 kilotons to 120 kilotons. A 50kt device would be about three times the size of the bomb that struck Hiroshima in 1945.
South Korea carried out live-fire exercises on Monday, simulating an attack on the North’s nuclear test site.
“Only the strongest sanctions will enable us to resolve this problem through diplomacy,” Ms Haley said.
“We have kicked the can down the road long enough. There is no more road left.”
She was speaking after US President Donald Trump warned the US might consider stopping all trade with any country doing business with North Korea.
“The United States will look at every country that does business with North Korea as a country that is giving aid to their reckless and dangerous nuclear intentions,” Ms Haley said.
The British ambassador to the UN, Matthew Rycroft, said direct talks with North Korea were only possible if Pyongyang stopped the escalation.
“Dialogue will always be our end goal but returning to dialogue without a serious sign of intent from Pyongyang would be a set-up to failure,” he said. “North Korea must change course to allow a return to dialogue.”
How big was the latest test?
It was North Korea’s sixth and most powerful nuclear test to date. The US Geological Survey recorded a resulting tremor at 6.3 magnitude.
Kim Jong-un was shown on camera posing with what state media said was a new type of hydrogen bomb.
South Korea said it was now presumed the North had reduced its nuclear warhead in size to below 500kg (1,100lbs), and would be able to attach one to an intercontinental ballistic missile.
But analysts have said the North’s claims about miniaturisation should be treated with considerable caution.
How are the South and its US ally responding?
Monday’s drills simulated the targeting of the Punggye-ri nuclear site in Kilju County, where North Korea carried out its bomb test. Missiles were fired from the ground and rockets from fighter jets.
The defence ministry in Seoul said there would be more live-fire drills in the South this month, involving Taurus air-to-surface missiles mounted on F-15 jets.
The ministry also told parliament the US would seek to deploy a nuclear-powered aircraft carrier to seas off the peninsula.
Four more launchers of the US Thaad (Terminal High-Altitude Area Defence) missile defence system -strongly opposed by China and Russia – would also be deployed to join two already at a site in Seongju, south of Seoul.
South Korea and the US have also agreed “in principle” to revise current guidelines so that the South can double the maximum payload of its ballistic missiles, the Yonhap news agency reports.