US Secretary of State Rex Tillerson has said it is a "matter of time" before North Korea gains the ability to strike the American mainland with a nuclear weapon.
His statement came as he chaired a ministerial level meeting at the United Nations Security Council in New York, where he urged the organisation to agree new economic and diplomatic pressures on Pyongyang.
The approach stood slightly at odds with President Donald Trump's escalating rhetoric on the issue.
In an interview with the Reuters news agency, Mr Trump said a "major, major conflict" with North Korea is possible.
He has repeatedly insisted that "all options are on the table", including the use of military force.
Mr Tillerson singled out China during his remarks, imploring Beijing to use its relationship with North Korea to influence the unpredictable nation.
UK Foreign Secretary Boris Johnson echoed his counterpart's words.
He said: "There could hardly be a clearer threat to world peace, more demanding of a unified response, than the activities of one member of the United Nations, North Korea, breaking its Treaty obligations, ignoring the will of this Council, and making blood-curdling threats to inflict grievous harm on peoples of other countries.
"We urge other partners with direct influence on North Korea to use their leverage to the full, with the aim of easing tensions and ensuring compliance with the expressed will of the UN."
However China seems reluctant to do so.
Addressing the Security Council chamber, China's foreign minister Wang Yi said the answer to the problem did not lie with his country.
He warned that the use of force in the region would lead to "disaster", and that the existing situation could easily "spiral out of control".
And North Korea said the country's nuclear weapons would never be part of "political bargains and economic deals".
"In a nutshell, DPRK have already declared not to attend any type of talks which would discuss its nuclear abandonment, nuclear disbandment," deputy UN ambassador Kim In Ryong said.
He added that the nuclear programmed "is the product of the United States' hostile policy towards DPRK".
"That is why every solution will be possible when the United States hostile policy is withdrawn in advance."