US Secretary of State Rex Tillerson has held a door open for dialogue with North Korea, saying Washington is willing to talk to Pyongyang if it ends a series of recent missile test launches.
Mr Tillerson's comments, made at a regional security forum in Manila, were the latest US attempt to rein in Pyongyang's nuclear and missile program after months of tough talk from US President Donald Trump.
The UN Security Council on Saturday imposed its toughest round of sanctions yet against Pyongyang over its two intercontinental ballistic missile tests in July.
North Korea responded as expected on Tuesday (NZT), saying the UN moves were unwarranted and unfair, and it was ready to teach the US a "severe lesson" if it attacked.
But Mr Tillerson appeared conciliatory on Tuesday.
"When the conditions are right, then we can sit and have a dialogue around the future of North Korea so they feel secure and prosper economically," Mr Tillerson told reporters.
"The best signal that North Korea can give us that they are prepared to talk would be to stop these missile launches," he said.
"We've not had an extended period of time where they have not taken some type of provocative action by launching ballistic missiles."
Mr Tillerson said Washington would not "specify a specific number of days or weeks" before deciding that North Korea had indeed halted its tests.
The Trump administration's attempts to pressure North Korea into abandoning its nuclear ambitions have so far gained little traction, and Pyongyang has only stepped up its tests, launching two intercontinental ballistic missile tests last month.
Mr Tillerson said the support of China and Russia for the latest sanctions sent a strong message to North Korea about what was expected of it.
South Korean President Moon Jae-in and President Trump agreed to apply maximum pressure and sanctions on North Korea in a telephone call on Monday, while China expressed hope that North and South Korea could resume contact soon.