President TrumpDonald John TrumpDems want tougher language on election security in defense bill Five aides to Van Drew resign ahead of his formal switch to GOP The myth of the conservative bestseller MORE said Monday that he would be “disappointed” if North Korea had something “in the works” with respect to its nuclear program.

“I would be disappointed if something would be in the works, and if it is, we will take care of it,” Trump told reporters during a roundtable discussion with governors at the White House when asked whether he was concerned about potential developments.

“We’re watching it very closely,” Trump continued, adding that he's watching “many places” very closely.  

North Korea had set a year-end deadline for the United States to make concessions in talks over its nuclear program, hinting that it would resume testing nuclear and long-range missiles otherwise. Pyongyang has also cryptically threatened to give the U.S. a “Christmas gift,” stirring speculation of a year-end missile test. 

Trump has made negotiating with North Korea in an effort to dismantle Pyongyang’s nuclear program a key prong of his foreign policy.

Those efforts have largely stalled, however, after Trump ended a February summit with North Korean leader Kim Jong UnKim Jong UnWashington braces as North Korea deadline looms North Korea is everybody's problem, so Trump must change his approach North Korea conducts 'crucial test' from rocket launch site MORE early without any agreement. North Korea has also resumed test launches of short-range missiles, touting two “crucial” tests in recent weeks.

U.S. special envoy to North Korea Stephen Biegun traveled to the region this week and warned Pyongyang against conducting major weapons tests.

“We are fully aware of the strong potential for North Korea to conduct a major provocation in the days ahead,” Biegun, whom Trump has tapped to be deputy secretary of State, said in Seoul, South Korea, on Monday.

“Such an action will be most unhelpful in achieving a lasting peace on the Korean Peninsula,” Biegun continued.

Trump has repeatedly touted his relationship with Kim as a positive and has at times downplayed Pyongyang’s missile tests in recent months.

At a NATO meeting in London earlier this month, Trump said he hoped Kim would denuclearize while noting that the U.S. has “the most powerful military” and would use it “if we have to.” 

“I have confidence in him. I like him. He likes me. We have a good relationship,” Trump told reporters on Dec. 3. “We'll see what happens. He definitely likes sending rockets up, doesn’t he? That’s why I call him ‘Rocket Man.’”

The remarks drew ire from Pyongyang, which threatened to resume calling Trump a “dotard.”