US Secretary of State Mike Pompeo has said he expects North Korea’s leader will live up to his commitment not to resume nuclear and missile tests.
Mr Pompeo said Kim Jong-un had promised US President Donald Trump in Vietnam that testing would not resume.
His comments follow a suggestion by North Korean-Vice Foreign Minister Choe Sun-hui that denuclearisation talks might end and testing could resume.
The US says sanctions will remain until Pyongyang destroys all nuclear sites.
Mr Pompeo told reporters on Friday that “on multiple occasions [Mr Kim] spoke directly to the president and made a commitment that he would not resume nuclear testing, nor would he resume missile testing” during their February summit.
“That’s Chairman Kim’s word,” Mr Pompeo said. “We have every expectation that he will live up to that commitment.”
Earlier, Ms Choe said US diplomats had thrown away “a golden opportunity” during the summit when North Korea offered to dismantle its main Yongbyon nuclear complex.
Talks in Hanoi collapsed when Mr Trump refused to lift any sanctions until North Korea was completely denuclearised.
But Mr Pompeo said he is “hopeful” that discussions will continue.
“I saw the remarks [Ms Choe] made – she left open the possibility negotiations would continue. It’s the administration’s desire that we continue to have conversations around this.”