WASHINGTON President Donald Trump on Tuesday threatened North Korea, promising fire and fury like the world has never seen, following new reports the country has escalated its nuclear program .

North Korea best not make any more threats to the United States. They will be met with fire and fury like the world has never seen, he said in a short statement to reporters at his golf club in Bedminster, New Jersey, before a meeting on the opioid crisis.

He has been very threatening, beyond a normal statement, Trump said of the countrys leader, Kim Jong Un. And as I said, they will be met with fire, fury and frankly, power, the likes of which this world has never seen before.

Trumps ultimatum, which mirrors North Koreas rhetoric toward the United States , came as U.S. intelligence officials reportedly learned that North Korea has produced a miniaturized nuclear warhead that could be placed on a missile , a significant step in advancing its nuclear program.

A few hours after Trumps news conference, North Koreas official KCNA news agency carried a series of statements from military spokesmen responding to the presidents rhetoric. Using bombastic language typical to KCNA statements, a spokesman claimed that Pyonyang was carefully examining plans to launch missiles at the U.S. island territory of Guam.

In a separate post, another North Korean military spokesman warned that war is by no means a game and claimed that U.S. war-thirsty forces are engrossed in war hysteria without discretion. KCNA also published a post titled U.S. Reckless War Frenzy Slammed, in which the propaganda arm blamed Washington for making plans to carry out a pre-emptive strike against North Korea.

In recent weeks, the country has also claimed that it successfully tested two intercontinental ballistic missiles, which may be capable of reaching Alaska.

U.S. intelligence officials do not know whether North Korea has tested the miniaturized warhead yet, according to NBC News and The Washington Post .

On Monday, North Korea issued a similarly strong threat to the U.S.

Should the U.S. pounce upon the DPRK with military force at last, the DPRK is ready to teach the U.S. a severe lesson with its strategic nuclear force, foreign minister Ri Yong Ho said in a statement , referring to North Korea.

Trump has regularly responded to North Koreas nuclear escalation with little specificity, insisting that all options are on the table. He has taken particular issue with China , North Koreas only ally, for not doing more to rein in the nuclear program and suggested economic consequences against the country, an important U.S. trade partner.

Sen. John McCain (R-Ariz.), chairman of the Senate Armed Services Committee, criticized Trumps rhetoric in an interview with KTAR radio on Tuesday.

I take exception to the presidents comments because youve got to be able to do what you say youre going to do, McCain said. In other words, the old walk softly but carry a big stick, Teddy Roosevelts saying, which I think is something that shouldve applied because all its going to do is bring us closer to a serious confrontation.

McCain, however, said he was unsure of whether Trumps statement could be interpreted as a threat to North Korea. I dont know what hes saying and Ive long ago given up trying to interpret what he says. Its not terrible, but its kind of the classic Trump in that he overstates things.

Later Tuesday, Guams congressional delegate Madeleine Bordallo responded to North Koreas provocation, saying she was confident that Guam remains safe and protected .

I am confident in the ability of U.S. defenses to protect our island and allies in the region, she said.

Meanwhile, Secretary of State Rex Tillerson is meeting with officials in Asia this week, exploring diplomatic solutions to the growing crisis .

This story has been updated to include comments from Sen. John McCain and Del. Madeleine Bordallo.

CORRECTION: A previous version of this story misstated that KTAR was an AM station in Glendale, Arizona. It is an FM station and is based in Phoenix.