WASHINGTON — Treasury Secretary Steven Mnuchin said Sunday that President Donald Trump will demand North Korea denuclearize during a meeting with leader Kim Jung Un that is anticipated to take place in the coming months.

"Absolutely, we've been very clear on it," Mnuchin said in an exclusive interview with "Meet the Press" when asked if denuclearization of the Korean Peninsula is still U.S. policy. "That's the objective and that's what we're going to accomplish."

Trump's surprise announcement Thursday that he would be willing to meet with Kim has been met with skepticism from those worried that Kim has little interest in sticking to any agreement following the high-profile summit. The proposed talks, which have been a long-held goal of North Korean leaders, come amid heightened tensions between the two nations. Over the past year, Pyongyang has launched multiple missile tests, some over Japan, and has threatened the U.S. territory of Guam.

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Earlier on Saturday night, Trump hit the campaign trail for Republican House candidate Rick Saccone and spoke at a rally in Moon, Pennsylvania. In the long, apparently off-the-cuff address, the president widely attacked the media while telling a crowd of supporters to "be very nice" to Kim.

The president also derided Democratic lawmakers, calling Rep. Maxine Waters "a very low I.Q. individual" and referred to a member of the press using an expletive.

"He's using those vulgarities in the context of a campaign rally," Mnuchin said. "And obviously there were a lot of funny moments on that rally."

"You know he likes to put names on people," Mnuchin added. "He did that through the entire presidential election, including all the Republicans that he beat. So these are campaign rally issues."

On the issue of North Korea, Mnuchin added that Kim is willing to temporarily halt the country's nuclear testing because of crippling economic sanctions enforced by the Trump administration.

"There's no question these sanctions are working and that's what brought them to the table," Mnuchin said.

"I don't think anybody really believes that North Korea is prepared to denuclearize," said Republican Sen. Jeff Flake, who also appeared on "Meet The Press." "Now, maybe a freeze where they say, 'All right. We are a nuclear power. Let's get some security guarantees.' But denuclearization, [as] I've heard it suggested, that that's what the North Koreans have already agreed to, I would question that."

Democratic Sen. Elizabeth Warren, who also appeared on the program, expressed concerns as well.

"I am very worried that they're going to take advantage of him," she said. "And it starts right where you asked this question. And that is leaders of North Korea, for a very long time, the Kim family, has wanted to meet face-to-face with a U.S. president. That is a win for them."