President Donald Trump just canceled his meeting with Kim Jong Un scheduled for next month in Singapore because North Korea was mean to Vice President Mike Pence.

Trump made the call Thursday morning over the “tremendous anger and open hostility” North Korea showed in a recent statement about the vice president, the president wrote in a letter to “chairman” Kim.

Just hours earlier, North Korea labeled Pence a “political dummy, ignorant, and stupid.” The Hermit Kingdom also threatened to “make the U.S. taste an appalling tragedy it has neither experienced nor even imagined” and added that if the summit did not go ahead, it would result in a “nuclear-to-nuclear showdown.”

Also hours earlier, foreign journalists confirmed that North Korea had followed through on its promise to destroy its Punggye-ri nuclear test site.

Trump, however, didn’t completely close the door on a future meeting and wrote that he looks forward to meeting Kim “some day.” Trump also noted that if Kim changed his mind about the Singapore summit, then he should call or write to Trump — though it’s unclear what that means, given Trump was the one who cancelled the meeting.

Both Trump and Kim had been threatening to cancel the summit ever since it was announced in March. Trump had warned that he was willing to walk away from the negotiating table if he didn’t get his way, and earlier this week, he hinted he was about to cancel: “There's a very substantial chance that it won't work out.”

Kim had also threatened to call off the meeting. He first complained about ongoing military exercises between the U.S. and South Korea and then blasted comments made by National Security Adviser John Bolton that North Korea could follow a “Llibya model” of denuclearization.

Secretary of State Mike Pompeo gave some more background on why Trump made his decision Thursday morning. He told the Senate Foreign Relations Committee that North Korea simply did not respond to repeated requests from U.S. officials to discuss the logistics of the Singapore summit.

"Over the past many days, we have endeavored to do what Chairman Kim and I had agreed, was to put teams, preparation teams together to begin to work to prepare for the summit, and we had received no response to our inquiries from them,” Pompeo said.

Here's the full text of Trump's letter to Kim: