nikki haley
U.S. Ambassador to the United Nations Nikki Haley was prank-called by two Russian comedians. Here, Nikki Haley prepares to speak on the floor of the General Assembly in New York City, Dec. 21, 2017. Spencer Platt/Getty Images

U.S. ambassador to the United Nations Nikki Haley said that President Donald Trump needs to keep North Korean leader Kim Jong Un “on his toes,” referring to an explosive tweet in which the president said he had a bigger nuclear button than Kim.

“I think [Trump] always has to keep Kim on his toes. It’s very important that we don’t ever let [Kim] get so arrogant that he doesn’t realize the reality of what would happen if he started a nuclear war,” said Haley Sunday on ABC’s “This Week.”

Trump’s tweet Tuesday was in reaction to Kim’s New Year’s speech in which he said “the button for nuclear weapons is on my table,” and that he could use it against the U.S.

“North Korean Leader Kim Jong Un just stated that the “Nuclear Button is on his desk at all times.” Will someone from his depleted and food starved regime please inform him that I too have a Nuclear Button, but it is a much bigger & more powerful one than his, and my Button works!” tweeted the president earlier this week.

Haley rebuffed the show’s host George Stephanopoulos who countered that Senate Republicans Cory Gardner of Colorado and John Cornyn of Texas called the tweet reckless.

“You know, everyone’s going to have their opinion. What I can tell you is I’m dealing with the diplomats on the ground, I’m dealing with all the actors in this situation,” said Haley. “It is a serious situation and [Kim] can’t sit there and imply that he’s going to destroy the United States without us reminding him of the facts and the reality that if you go there, it’s not us that’s going to be destroyed, it’s you.”

Last year, North Korea tested its sixth and largest nuclear weapon, which they claimed to be a hydrogen bomb, and demonstrated the theoretical ability to strike anywhere in the U.S. with an intercontinental ballistic missile.

CIA director Mike Pompeo also defended the tweet Sunday saying it was “consistent with U.S. policy,” on CBS’ “Face the Nation.” Pompeo pointed out that U.S. sought the denuclearization of North Korea. Pompeo also pushed back against a Saturday New York Times article which said U.S. intelligence had underestimated North Korea’s missile capabilities.

North Korea and South Korea are set to talk Tuesday for the first time in over two years, and Pompeo attributed the diplomatic breakthrough to Trump's rhetoric on “Fox News Sunday.” The president also took credit for the talks in a Thursday tweet.

“With all of the failed “experts” weighing in, does anybody really believe that talks and dialogue would be going on between North and South Korea right now if I wasn’t firm, strong and willing to commit our total 'might' against the North. Fools, but talks are a good thing!” the president tweeted.

The president said Saturday that he supported conditional talks with North Korea at a press conference at Camp David. Trump’s new stance marks a reversal from October when he tweeted at Secretary of State Rex Tillerson that talks with North Korea were a waste of time.

Haley, however, characterized the change in stance differently.

“There is no turnaround,” Haley told ABC. “What [Trump] has basically said is ‘Yes, there could be a time when we talk to North Korea but a lot of things have to happen before that actually takes place. They have to be willing to talk about banning their nuclear weapons.’”

The talks between the two nations will center on North Korea's participation in the Winter Olympics in South Korea next month.