North Korea yesterday ruled out any negotiations over its nuclear weapons and missile programmes, and accused the United States of rigging a weekend UN Security Council vote that approved new sanctions aimed at curbing the North's export earnings.
"We will, under no circumstances, put the nukes and ballistic rockets on the negotiating table," the North's Foreign Minister Ri Yong Ho said in remarks delivered at the Asean Regional Forum here.
He insisted his nation's nuclear arsenal "is an inevitable strategic option, and it is a precious strategic asset that can neither be reversed nor bartered for anything".
Pyongyang's response came after the United Nations Security Council unanimously imposed new sanctions aimed at pressuring North Korea to end its nuclear programme after two intercontinental ballistic missile (ICBM) tests last month.
The sanctions could slash North Korea's US$3 billion (S$4 billion) annual export revenue by a third.
Mr Ri called the sanctions "fabricated", and insisted the UN had abused its authority.
He said the North's ICBM tests last month proved that the entire US was in firing range, and that those missiles were a legitimate means of self-defence.
North Korea is ready to give the US a "severe lesson" if it takes military action against it, he warned.
Chinese Foreign Minister Wang Yi said China would strictly implement the sanctions "100 per cent".
"The key is that we cannot let the situation continue to escalate, and we need to find an opportunity to turn things around amid the crisis," he told reporters.
Mr Wang held direct talks with Mr Ri on Sunday, telling him in unusually strong terms: "Do not violate the UN's decision or provoke the international society's goodwill by conducting missile launching or nuclear tests."
In a news briefing, Japanese Foreign Minister Taro Kono said "heated discussions" took place about North Korea's missile tests, and most countries believed UN sanctions on Pyongyang should be fully implemented.
Earlier in the day, US Secretary of State Rex Tillerson ruled out a quick return to dialogue with North Korea, as he said new UN sanctions showed the world had run out of patience with Pyongyang's nuclear weapons programme.
He told reporters that Washington would consider talks only if Pyongyang halted its ballistic missile tests.
"The best signal that North Korea could send that they are prepared to talk would be to stop these missile launches," he said, holding out the prospect of US envoys sitting down with Pyongyang's isolated regime.
But he would not set a timeframe on when this might be possible or how long North Korea might have to refrain from testing more long- range missiles.
"We will know it when we see it," he told reporters.
"I am not going to give someone a specific number of days or weeks. This is really about the spirit of these talks. And they can demonstrate that they are ready to sit in the spirit of finding their way forward in these talks by no longer conducting these missile tests."
On another thorny issue confronting Washington, Mr Tillerson said he believed the US and Russia could find a way to ease tensions, saying it would not be useful to cut ties over the single issue of suspected Russian meddling in last year's US presidential election.
He said Russia had also expressed some willingness to resume talks about the crisis in Ukraine, where a 2015 ceasefire between Kiev's forces and Russian-backed separatists in the eastern part of the country is regularly violated.
"We should find places we can work together... In places we have differences, we are going to have to continue to find ways to address those," he told reporters.