ANDERSEN AIR FORCE BASE, Guam — Secretary of State Rex Tillerson on Wednesday defended President Trump’s forceful warning to North Korea to stop threatening the United States, and dismissed concerns that Guam is in any imminent danger from Pyongyang’s missiles.

“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 in an interview with two pool reporters while flying from Malaysia to a scheduled refueling stop in Guam.

“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.”

On Tuesday, Trump sharply ratcheted up rhetoric against North Korea, saying it would face “fire and fury” if it does not stop threatening the United States. Trump did not make clear whether he was responding to the latest bellicose remarks from North Korea or a report in The Washington Post that the North had successfully produced a miniaturized nuclear warhead capable of fitting inside its ballistic missiles.

Hours after Trump’s comments, North Korea said it was preparing to send intermediate-range missiles near Guam, which is home to more than 160,000 U.S. citizens, including some 6,000 members of the armed forces. U.S. bombers have flown out of Guam on their way to joint exercises with South Korea and Japan over the Korean Peninsula.

Tillerson is returning home from Asia, where he continued his campaign to get more countries fully enforcing U.N. sanctions against North Korea over its ballistic missile and nuclear testing, with an ultimate aim of forcing it to the bargaining table.

During Tillerson’s stop in Guam — which included brief meetings with some U.S. military personnel — Trump called attention to the might of the U.S. nuclear arsenal. In Twitter posts, Trump did not specifically mention North Korea, but the messages came as attention was focused on the confrontation with Pyongyang.

Trump asserted that U.S. nuclear power was “now far stronger and more powerful than ever” after his administration moved to “renovate and modernize” the arsenal.

“Hopefully we will never have to use this power, but there will never be a time that we are not the most powerful nation in the world!” Trump wrote.

While Pyongyang has been making bombastic threats against the United States for some time, as the pace of its testing has accelerated its warnings have grown more specific and directed against the United States.

On Monday in Manila, where Tillerson was attending a regional security conference, North Korean Foreign Minister Ri Yong Ho issued a lengthy statement vowing that his country would never relinquish its nuclear weapons. Ri said the “nukes” would be used only against the United States, and he asserted that the entire U.S. mainland is within range of North Korean missiles.

Tillerson said Guam is in no more danger than anywhere else, adding that North Korea’s threats naming the island as a target did not deter him from making a scheduled refueling stop here.

“Well, the North Korean missile capability can point at many directions,” he said. “So Guam is not the only place that can be under threat. No, I never considered rerouting the trip back. And I do not believe that there is any imminent threat, in my own view.”

Tillerson said North Korea’s rhetoric shows that the campaign to turn Pyongyang’s allies against it is working.

Russia and China, North Korea’s main economic lifelines, both supported a new set of U.N. sanctions passed last weekend that could cut the country’s revenue by a third. And the Association of Southeast Asian Nations approved a statement expressing “grave concern” over North Korea’s actions.

Tillerson said he knew of no significant changes in the last 24 hours that could speed a move to military action. Nor does he see any reason for a change in strategy. Diplomatic and economic isolation is working, he said, even if it could take a long time to materialize.

“I think in fact the pressure is starting to show,” he said. “I think that’s why the rhetoric coming out of Pyongyang has gotten louder and more threatening.”

Tillerson also said Americans should not worry about the increasingly angry tone displayed in recent days.

“I think what the president was just reaffirming is that the United States has the capability to fully defend itself from any attack, and our allies, and we will do so,” he said. “So the American people should sleep well at night.”

Key U.S. allies, meanwhile, called for a greater push to open talks with North Korea.

The spokeswoman for EU foreign policy chief Federica Mogherini said “a lasting peace and denuclearization of the Korean Peninsula must be achieved through peaceful means.”

“That excludes military action,” said the spokeswoman, Catherine Ray.

In New Zealand, Prime Minister Bill English called Trump’s comments “not helpful” in a standoff that was already “very tense.”

Washington Post writer Brian Murphy contributed to this report.