President Donald Trump went after Kim Jong Un during a campaign rally for Sen. Luther Strange (R-Ala.) in Alabama on Friday night, the latest barb in the ongoing exchange of threats and insults between the two leaders.

Trump called the North Korean dictator a “mad man” and “rocket man” during the endorsement speech for Strange, echoing insults the president made against Kim earlier this week at the United Nations General Assembly.

“I believe the best path to the most peaceful world are proud, independent sovereign nations that respect their people,” Trump said to the Alabama crowd.

“We can’t have mad men out there shooting rockets all over the place,” he added. “And, by the way, rocket man should’ve been handled a long time ago ... This shouldn’t be handled now, but I’m going to handle it because we have to handle it.”

“Little rocket man,” the president continued. “We’re going to do it because we really have no choice. He’s talking about a massive weapon exploding over the ocean ... which causes tremendous calamity.”

Trump did suggest that diplomatic solutions with North Korea over its weapons programs could be reached, saying “maybe something gets worked out and maybe it doesn’t.” But he appeared to walk that back almost immediately by adding, “Personally, I’m not sure that it will.”

Trump’s remarks Friday night, came several hours after he tweeted that Kim was a “madman” who would be “tested like never before.”

Kim Jong Un of North Korea, who is obviously a madman who doesn't mind starving or killing his people, will be tested like never before! — Donald J. Trump (@realDonaldTrump) September 22, 2017

Trump and Kim have been lobbing threats at each other over the past few months, with this latest round tipped off by Trump’s speech at the U.N. on Tuesday. In front of his fellow world leaders, Trump told the General Assembly that “Rocket Man is on a suicide mission” and said that the U.S. “will have no choice but to totally destroy North Korea” if Kim’s regime doesn’t back down from its nuclear development programs.

In response to that speech, Kim said in a statement that he’d “tame the mentally deranged U.S. dotard with fire.” Hours later, the North Korean foreign minister threatened to test a hydrogen bomb somewhere in the Pacific.

Trump on Thursday tightened its grip on North Korea by ordering stricter sanctions against the isolated country, which would force countries to choose between doing business with the U.S. or North Korea.