The United States said Sunday the time for talk over North Korea was "over," spurning a UN response to Pyongyang's latest ICBM launch in favour of bomber flights and missile defence system tests.
Nikki Haley, the US envoy to the United Nations, said there was "no point" in holding a fruitless emergency Security Council session, warning that a weak additional council resolution would be "worse than nothing" in light of the North's repeated violations.
North Korean leader Kim Jong-Un boasted of his country's ability to strike any target in the US after an intercontinental ballistic missile test Friday that weapons experts said could even bring New York into range -- in a major challenge to Trump.
US strategic bombers on Saturday flew over the Korean peninsula in a direct response to the launch, and on Sunday American forces successfully tested a missile interception system the US hopes will be installed on the Korean peninsula.
Under Kim's leadership, North Korea has accelerated its drive towards a credible nuclear strike capability, in defiance of international condemnation and multiple sets of UN sanctions. The US Senate passed new bipartisan sanctions on Pyongyang on Friday.
Haley urged China, Japan and South Korea to tighten the screws on Pyongyang.
"An additional Security Council resolution that does not significantly increase the international pressure on North Korea is of no value," she wrote.
"It sends the message to the North Korean dictator that the international community is unwilling to seriously challenge him.
"China must decide whether it is finally willing to take this vital step. The time for talk is over."
Earlier, US President Donald Trump warned that he would not allow China -- the impoverished North's sole major ally and economic lifeline -- to "do nothing" about Pyongyang.
In two tweets, Trump linked trade strains with the Asian giant -- marked by a trade deficit of $309 billion last year -- to policy on North Korea, after Seoul indicated it could speed up the deployment of a US missile defense system that has infuriated China.