En route to Guam today coming off an Asian trip that included Manila, Bangkok and Kuala Lumpur, Secretary of State Rex Tillerson said President Trump threatened to rain “fire and fury” on North Korea because Kim Jong-un “doesn’t seem to understand diplomatic language.”

At the conclusion of comments about opioid addiction during a roundtable meeting on the crisis Tuesday at his golf club in Bedminster, N.J., President Trump was asked about reports that Pyongyang had succeeded or potentially succeeded in miniaturizing a nuclear warhead to fit atop an intercontinental ballistic missile.

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

Some lawmakers took issue with the comments. “Isolating the North Koreans has not halted their pursuit of nuclear weapons. And President Trump is not helping the situation with his bombastic comments,” said Sen. Dianne Feinstein (D-Calif.).

“I take exception to the president’s comments because you gotta be able to do what you say you’re gonna do,” Sen. John McCain (R-Ariz.) told KTAR radio Tuesday. ” I don’t think that’s a way you attack an issue and a challenge like this.”

In return, North Korea said it was studying plans to attack the U.S. “air pirates” bases in Guam and would be ready to launch such an attack the minute Kim Jong-un gave a green light.

Tillerson told reporters that as “the North Koreans’ rhetoric has just ratcheted up louder and louder and more threatening,” what Trump 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.”

“I think the president just wanted to be clear to the North Korean regime that the U.S.’, you know, 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,” he added.

Asked about the Guam threat, Tillerson replied, “Well, look, the North Korean missile capability is pointed in many directions.”

“So Guam is not the only place that could be under threat. No, I never considered rerouting the trip back. I do not believe that there is any imminent threat, in my own view,” he said.

Asked if there is a longer-term threat to Guam, the secretary of State said, “Well, I hope not.”

“Again, what we’re hopeful is that this pressure campaign which the entire world now has joined us in, and with the engagement of China and Russia, two of North Korea’s closest neighbors, that they can begin to persuade the regime that they need to reconsider the current pathway they’re on; think about engaging in a dialogue about a different future,” Tillerson added.

He said he hadn’t talked with China and Russia in about a day and a half.

“I have nothing that I have seen, and nothing that I know of would indicate that the situation has dramatically changed in the last 24 hours,” Tillerson said, stressing that the U.S. doesn’t have plans to rethink strategy.

“I think in fact the pressure is starting to show. I think that’s why the rhetoric coming out of Pyongyang is beginning to become louder and more threatening. Whether we’ve got them backed into a corner or not is difficult to say, but diplomatically you never like to have someone in a corner without a way for them to get out.”

That way out? “Talks with the right expectation of what those talks will be about,” Tillerson said.

“I think Americans should sleep well at night, have no concerns about this particular rhetoric over the last few days. I think the president, again, as commander in chief, I think he felt it necessary to issue a very strong statement directly to North Korea. But I think what the president was just reaffirming is the United States has the capability to fully defend itself from any attack and defend our allies, and we will do so,” he said. “So the American people should sleep well tonight.”