Defense Secretary Jim Mattis warned North Korea on Wednesday that its actions “will continue to be grossly overmatched by ours,” and that Pyongyang would lose any arms race or conflict that it starts with the United States.

The comments came amid an escalating war of words between North Korea and President Trump, who used extraordinary rhetoric Tuesday afternoon by warning Pyongyang that continued threats would be “met with fire and fury and frankly power, the likes of which this world has never seen before.” North Korea responded by saying it is considering a preemptive missile strike against Guam, a U.S. island territory in the Pacific that is home to an Air Force base, Navy submarines armed with nuclear weapons and other military forces.

Mattis said in a statement that Trump was informed of the growing threat that North Korea poses in December before he took office, and ordered the Pentagon to emphasize ballistic missile defense and nuclear weapons that pose a deterrent to other countries using them.

“While our State Department is making every effort to resolve this global threat through diplomatic means, it must be noted that the combined allied militaries now possess the most precise, rehearsed and robust defensive and offensive capabilities on Earth,” Mattis said. He added that North Korea “should cease any consideration of actions that would lead to the end of its regime and the destruction of its people.”

But the defense secretary’s remarks were still notably more measured than the president’s. Mattis, rather than threatening to strike if North Korea continues to make threats, said that North Korea “would lose any arms race of conflict it initiates,” which adheres to a long-standing policy of attempting to deter North Korea with the promise of a swift, overwhelming response to any attack.

Mattis, who was traveling on the West Coast, released his statement after Trump continued to issue threats Wednesday morning. In a pair of tweets, the president said that his first order after taking office was to renovate and modernize the nuclear arsenal, and it is “now far stronger and more powerful than ever before.”

In reality, while the U.S. maintains more nuclear weapons than any other nation, most of them are decades old and the Pentagon is only beginning to embark on a years-long process to upgrade them.

Here's why North Korea threatened an island in the Pacific that's home to 160,000 people. (Victoria Walker, Danielle Kunitz/The Washington Post)

In separate comments, Secretary of State Rex Tillerson attempted in an interview Wednesday to assuage fears about Trump’s rhetoric.

“What the president is doing is sending a strong message to North Korea in language that Kim Jong Un would understand, because he doesn’t seem to understand diplomatic language,” Tillerson said. “I think the president just wanted to be clear to the North Korean regime that the U.S. has the unquestionable ability to defend itself, will defend itself and its allies, and I think it was important that he deliver that message to avoid any miscalculation on their part.”

Mattis has warned that North Korea now poses the most urgent threat to U.S. peace and security, but also that any war with Pyongyang would include “probably the worst kind of fighting in most people’s lifetime,” citing the threat posed by hundreds of North Korean rocket launchers and artillery pieces aimed at Seoul.

The Pentagon has long preached strategic patience with North Korea, arguing that the United States must monitor the nation closely and have weapons that deter Pyongyang from military action. Retired Army Gen. Martin E. Dempsey, the Pentagon’s top general from October 2011 to September 2015, advocated staying on that path now.

“We control the clock,” he wrote. “Need steady, calculated, creative, inclusive leadership.”

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