Landing in Japan on the first stop of his marathon five-nation tour of Asia, U.S. President Donald Trump on Sunday called the nation a “treasured partner” and “crucial ally” of the United States while asserting that “no dictator” and “no regime” should ever underestimate America — a not-so-veiled rebuke of nuclear-armed North Korea.

After paying a solemn visit to Pearl Harbor and the USS Arizona Memorial in Hawaii on Friday, Trump on Sunday marked the start of his trip to Asia by disembarking from Air Force One at the U.S. Air Force’s Yokota Air Base in western Tokyo. Cheers erupted as he appeared on stage with his wife, first lady Melania Trump, prompting thousands of U.S. military personnel there to welcome the pair with enthusiastic chants of “USA! USA! USA!”

“Japan is a treasured partner and crucial ally of the Unites States,” Trump told a packed aircraft hangar after changing into a bomber jacket. “Today we thank them for decades of wonderful friendship between our two nations.”

It was the first visit by Trump to Japan since his astonishing rise to the presidency last year. The trip will give him and Prime Minister Shinzo Abe — touted as one of his best friends among world leaders — a chance to reaffirm their shared strategy of piling “maximum pressure” on the North while also demonstrating anew the strength of the two nations’ alliance.

After delivering his speech, Trump flew to Kasumigaseki Country Club in Saitama Prefecture for two hours of golf diplomacy with Abe — an informal setting that also involved 25-year-old professional golfer Hideki Matsuyama.

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Before hitting the links, Abe presented Trump and Matsuyama with white baseball caps, each embroidered with the message “Donald & Shinzo Make Alliance Even Greater.” After nine holes, the two leaders were scheduled to enjoy a teppanyaki (iron-plate grill) steak dinner in Tokyo’s glitzy Ginza district.

But it was Trump’s speech at the Yokota base that had left the most indelible first impression from his visit.

There, Trump proudly exclaimed to the rowdy group of service members that “we dominate the sky. We dominate the sea. We dominate the land and space.”

The speech, infused with a hearty dose of patriotism, carefully avoided making any direct references to North Korea, which has this year test-fired missiles at a pace never seen before, including two that flew over the Japanese archipelago in August and September.

Still, Trump’s message was crystal clear to all watching: Mess with us, and you will be toast.

“Together with our allies, America’s warriors are prepared to defend our nation, using the full range of our unmatched capabilities. No one — no dictator, no regime and no nation — should underestimate, ever, American resolve,” he said.

“As long as I am president, the servicemen and women who defend our nation will have the equipment, the resources and the funding they need to secure our homeland, to respond to our enemies quickly and decisively, and when necessary to fight, to overpower and to always, always, always win,” he said, eliciting a burst of applause.

In another apparent dig at Pyongyang, Trump hailed U.S. military members as “brave warriors” who are the “greatest threat to tyrants and dictators who seek to prey on the innocent.”

The tyrant’s path, he said in an oblique reference to North Korean leader Kim Jong Un, is a “steady march toward poverty, suffering and servitude.”

Yokota is the headquarters of both U.S. Forces Japan and the ASDF’s Air Defense Command — a fact that some say makes it particularly at risk of a missile attack by the North. In August, the Air Self-Defense Force tested for the first time the deployment of Patriot Advanced Capability-3 (PAC-3) anti-missile systems at the base. The systems are designed to shoot down incoming short- and medium-range missiles in their terminal phase of flight.

“All of you have made Yokota one of the most capable operational bases in Japan, and actually anywhere in the world,” Trump said, adding that the base today serves as “a critical center for coordination for American and Japanese commanders to plan their missions.”

Senior airman Collin Eddington said Trump’s speech “really motivates us to do what we have been doing so far and keep doing the good job that we have been.”

Asked about North Korea’s repeated military provocations this year, Eddington said his team’s commitment to security remains unshaken.

“Yokota is as prepared and serious as we have always been,” he said after the ceremony wrapped up.

Monday will see Trump and Abe hold a summit dialogue where North Korea is expected to be a top issue. Trump is also scheduled that day to meet relatives of some of the Japanese abducted by North Korea in the 1970s and 1980s.

Aside from North Korea, another issue likely to be high on the agenda is Trump’s push for a more favorable bilateral trade deal with Japan to fill the vacuum left after Trump pulled the U.S. out of the multinational Trans-Pacific Partnership trade framework pursued by his predecessor, Barack Obama.

Kyodo News reported Saturday that Tokyo plans to sidestep the touchy issue even if Trump brings it up, to avoid creating a fissure in otherwise friendly ties between the two nations.

Over the next 10 days the U.S. leader will travel across Asia, including stops in South Korea and China, where he said he will seek “free, fair and reciprocal trade.”

“We will seek new opportunities for cooperation and commerce, and we will partner with friends and allies to pursue a free and open Indo-Pacific region,” he said.

The concept of a “free and open Indo-Pacific region” has been a key diplomatic goal for Abe, with its primary focus being to promote an international maritime order that is in line with the rule of law. The push is presumably designed as a counter to China’s growing assertiveness in the South and East China seas, although Tokyo maintains the stance that the strategy “targets no specific country.”