President Donald Trump tweeted a dire new warning to North Korea on Friday, saying the U.S. military is “locked and loaded” in case the country’s mercurial leader, Kim Jong Un, decides to “act unwisely.”

Military solutions are now fully in place,locked and loaded,should North Korea act unwisely. Hopefully Kim Jong Un will find another path! — Donald J. Trump (@realDonaldTrump) August 11, 2017

Speaking to reporters Friday afternoon, Trump said the meaning of his words should be apparent.

“What I said is what I mean,” Trump said. “Those words are very, very easy to understand.”

Trump again warned Kim not to make a move against the United States.

“If he utters one threat, which he’s been uttering for years... he will truly regret it, and he will regret it fast,” the president said.

Trump and North Korea have been locked in a war of words for days, beginning with Trump’s promise to unleash “fire and fury” on the isolated communist nation, which in July completed its first successful test of an intercontinental ballistic missile.

“He has been very threatening, beyond a normal statement,” Trump said of Kim on Tuesday, in comments that were reportedly off the cuff. “And as I said, they will be met with fire, fury and frankly, power, the likes of which this world has never seen before.”

North Korea responded hours later by accusing the U.S. of “war hysteria” and threatening to strike Guam. Trump then told reporters on Thursday that his previous threats may not have been “tough enough.”

Should North Korea attack the U.S. or one of its allies, Trump said that “things will happen to them like they never thought possible, OK? He’s been pushing the world around for a long time.”

Trump’s comments are notably more aggressive than the messaging from many in his administration, including Secretary of State Rex Tillerson and Defense Secretary James Mattis, who have said they will continue to pursue diplomatic talks rather than military action.

Foreign policy experts have criticized the president’s language as “reckless” and “dangerous.”

“That is about the stupidest and most dangerous statement I have ever heard an American president make,” John Mecklin, editor-in-chief of Bulletin of the Atomic Scientists, told HuffPost following Trump’s “fire and fury” remark.

“It increases the likelihood of nuclear war,” Mecklin added. “And those kind of threats are just not something an American president should make.”

This story has been updated with additional remarks from Trump. Paige Lavender contributed to this report.

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