The Trump administration has "reached out to the North Koreans" to ask them to resume diplomacy that has been all but dead since October, White House national security adviser Robert O'Brien told the Axios news website on Sunday.
"We've reached out to the North Koreans and let them know that we would like to continue the negotiations in Stockholm that were last undertaken in early October,” he said.
"We've been letting them know, through various channels, that we would like to get those [negotiations] back on track and to implement Chairman Kim's commitment" to denuclearization of the Korean Peninsula, added O’Brien.
O'Brien also indicated he was cautiously optimistic about the fact that Kim Jong Un hasn't yet delivered his promised "Christmas gift" which many analysts expected would be a nuclear weapons test.
Kim and President Donald Trump engaged in months of mutual insults and threats of devastation in 2017, sending tensions soaring before a diplomatic rapprochement the following year.
The pair have met three times since June 2018, most recently in Vietnam in February, but with little progress towards denuclearization.
Since that June meeting, North Korea has conducted several tests of ballistic missiles.
Kim had given Washington until the end of 2019 to make new concessions in talks over the country's nuclear arsenal.
In his New Year’s message after his ultimatum to the US expired, the North Korean leader said his country would continue developing nuclear programs unless the US gave up its hostile approach.
Trump recently sent a birthday message to Kim, but a North Korean official said on Saturday that the leader does not intend to restart nuclear talks.
O'Brien's predecessor as national security adviser, John Bolton, recently told Axios the Trump administration is bluffing about stopping North Korea's nuclear ambitions — and should prepare to admit publicly that its policy failed badly.
O'Brien indicated he was hopeful about the implications of Kim's decision — so far — to refrain from firing off a nuclear test in the Christmas and new year period.
Kim "promised to send a Christmas present," O'Brien said. "The president suggested he send him a vase. We didn't get a vase or any other sort of Christmas gift. That appears to be positive."
"All we know is we were told we were going to get a Christmas gift and the Christmas gift didn't come. And so I think that was an encouraging sign. But, again, that doesn't mean we won't see some sort of test in the future," O'Brien added.