Pyongyang has kept its economy afloat by sidestepping sanctions, using its local resources more efficiently and finding alternative ways to generate foreign cash.

In an effort to keep pressure on the U.S., North Korea has warned of making a perilous shift to its approach next year, when Mr. Trump will be facing re-election. On Friday, Pyongyang conducted a second significant test in a week at a satellite-launch facility, behavior that military experts believe could portend a long-range weapon launch.

A senior North Korean official warned in state media recently that the Trump administration’s next move will determine “what Christmas gift it will select.” The country’s U.N. ambassador said denuclearization was off the negotiating table earlier this month.

“I don’t think North Korea is under any pressure. They’re not in a rush for a deal,” said Robert Carlin, a former U.S. intelligence analyst who has been involved in prior negotiations with North Korea. “I’ve never seen these guys panic.”