Defense Secretary James Mattis on Wednesday warned North Korea that its people would be destroyed in a nuclear war with the US — an escalation of rhetoric as other administration officials were trying to downplay the threat.

“The DPRK must choose to stop isolating itself and stand down its pursuit of nuclear weapons,” Mattis said in a statement, using an acronym for North Korea.

“The DPRK should cease any consideration of actions that would lead to the end of its regime and the destruction of its people.”

He also had a stern, direct warning for the rogue nation’s dictator, Kim Jong Un.

“Kim Jong Un should take heed of the United Nations Security Council’s unified voice, and statements from governments the world over, who agree the DPRK poses a threat to global security and stability,” he said, according to The Hill.

President Trump on Wednesday declared the US nuclear arsenal “far stronger and more powerful than ever before” even as his top diplomat was working to calm the North Korea crisis and insisting there wasn’t “any imminent threat.”

In a series of early-morning tweets, Trump reaffirmed his threat from a day earlier by reposting the video of him warning that Pyongyang would be “met with fire and fury like the world has never seen” if it made more threats to the US.

President Trump vows America will respond to North Korean threats with “fire & fury” in a warning to the rogue nation pic.twitter.com/UaE2rPkZ6f — FOX & friends (@foxandfriends) August 9, 2017

The US arsenal is unchanged since Trump took office, and though a massive upgrade ordered last year by President Barack Obama is under way, it is still in the planning stages.

Only hours before Trump’s tweets, Secretary of State Rex Tillerson urged calm and said Americans should have “no concerns” despite the exchange of threats between the president and North Korea.

Aboard his plane, as he flew home from Asia, Tillerson insisted the developments didn’t suggest the US was moving closer to a military option for dealing with the crisis.

“Americans should sleep well at night,” Tillerson said

With Post wires