North Korea has one question for the United States: Naughty or nice?

The North delivered an ominous warning to Washington on Tuesday, saying that it is “up to the U.S. what Christmas gift it will select” as a year-end deadline for a “new approach” by the White House to stalled nuclear talks grows ever closer.

“Drawing nearer is the year-end time limit the DPRK set for the U.S.,” Vice Minister of Foreign Affairs Ri Thae Song said in a statement, referring to the North’s formal name, the Democratic People’s Republic of Korea.

“However, the U.S. is keen on earning time needed for it, talking about the ‘sustained and substantial dialogue,’ far from acting in response to the measures taken by the DPRK first,” Ri said, according to the statement carried by the official Korean Central News Agency.

Ri, a top diplomat for U.S. affairs, blasted Washington’s push for more nuclear talks as “nothing but a foolish trick hatched to keep the DPRK bound to dialogue and use it in favor of the political situation and election in the U.S.”

He said the North had “heard more than enough dialogue rhetoric” from the administration of President Donald Trump, and that “no one will lend an ear to the U.S. any longer.”

Ri used his statement to remind the U.S. of the deadline, set by North Korean leader Kim Jong Un, claiming that Pyongyang has “done its utmost with maximum perseverance not to backtrack from the important steps it has taken on its own initiative.”

“What is left to be done now is the U.S. option and it is entirely up to the U.S. what Christmas gift it will select,” Ri said.

Kim Jong Un has expressed his displeasure with the direction of the negotiations, analysts say, by conducting a flurry of weapons tests since May, including those of short-range missiles designed to evade missile-defense systems in South Korea and Japan.

Under U.N. Security Council resolutions, Pyongyang is banned from ballistic missile launches.

Some experts have said Kim could end his country’s self-imposed moratorium on nuclear tests and launches of intercontinental ballistic missiles capable of hitting U.S. cities if the deadline passes without any kind of progress.

“Maybe the end of the year deadline was the rope Kim was given to see if Trump could deliver fruit,” said Vipin Narang, a North Korea expert and professor of international relations at MIT. “And then if not: the new way. Which is the old way with ICBMs.”

Another option for getting Trump’s attention could be for the North to again lob an intermediate-range missile over Japan. Indeed, a top North Korean Foreign Ministry official warned Saturday that Tokyo could again see “a real ballistic missile” overflying the country “in the not distant future.”

In 2017, the North launched two separate intermediate-range missiles over Japan as Pyongyang underwent a massive expansion in its capabilities.

The nuclear negotiations between the U.S. and the North have effectively been deadlocked since working-level talks in early October ended with Pyongyang’s top negotiator, Kim Myong Gil, saying they had broken off “entirely due to the United States’ failure to abandon its outdated viewpoint and attitude.”

In recent weeks, senior North Korean officials have repeatedly criticized the U.S. over its position in the talks.

Kim and Trump have met three times. Their first meeting was at an official summit in Singapore in June last year, with a second one in February this year in Hanoi. In late June, the two leaders also met at the Demilitarized Zone separating the two Koreas.

Washington has voiced an eagerness to maintain dialogue with Pyongyang, with U.S. special envoy for North Korea Stephen Biegun saying late last month that the “window for diplomacy” with the nuclear-armed country “remains open.”

But the Hanoi summit, which collapsed over a disagreement over the lifting of sanctions and the level of denuclearization, is seen as an inflection point in the talks.

The easing of sanctions is widely believed to be at the top of the North’s wish list, something Kim signaled with his April 2018 speech announcing that rebuilding his country’s shattered economy was a top priority.

The Trump administration, however, has been reluctant to relinquish one of the few remaining pieces of leverage it holds over the Kim regime.

And while the two leaders had lavished praise on one another, senior North Korean officials have in recent weeks repeatedly criticized the U.S. over its position in the talks.

One top official formerly in charge of the negotiations, ex-spy chief Kim Yong Chol, even mocked the U.S. stance, saying the negotiations would not resume “before the complete and irrevocable withdrawal” of what Pyongyang calls the United States’ “hostile policy” toward the North.

That statement was remarkable for turning Washington’s long-standing demand for the North’s “complete, verifiable and irreversible denuclearization” on its head and portraying the White House as the recalcitrant party in the talks.

MIT’s Narang said Tuesday’s statement could signal that the White House had “underestimated” the effect the Hanoi summit collapse had on Kim and his strategy going forward.

“I always thought that Kim believed and understood that Trump was his best bet to look the other way while he builds and improves his nuclear and missile force, and to break the alliance with ROK,” he said, using the acronym for South Korea’s formal name, the Republic of Korea. “But it may be that we underestimated that the humiliation Kim faced at Hanoi, and potentially consequent pressure from his own hard-liners, outweighed that love for Trump.

“We will soon find out, as Ri Thae Song says, whether Trump is truly naughty or nice.”