SINGAPORE — For America’s allies in Asia, the outcome of President Trump’s summit meeting with Kim Jong Un of North Korea has been decidedly mixed.

On the good side, they no longer have to be on alert for the imminent outbreak of war on the Korean Peninsula.

But the widely anticipated Trump-Kim meeting on Tuesday left them with new anxieties. Trump’s concessions to North Korea exacerbated their fears about the United States’ long-term commitment to safeguarding the region.

Trump’s surprise declaration during a news conference after the summit that he would suspend military drills between the United States and South Korea — and that he hoped eventually to pull some 28,000 American troops off the peninsula — blindsided US allies, including South Korea itself. Even the Pentagon was caught off guard.

More broadly, Trump’s declaration raised questions about whether his outreach to the North actually signaled a US retreat from the region.

Since World War II, the United States has been a leader in East Asia, providing security assurances to allies in Japan and South Korea. But even before engaging in talks with North Korea, Trump had questioned the merits of stationing troops in the region and made it clear he thought the United States was paying too much to support them.

Suspending military drills would be a significant concession to North Korea, particularly as Trump echoed the North’s previous characterization of the exercises as “war games’’ and “provocative.’’ The fact that he appeared to make this decision without informing the Pentagon, never mind officials in Seoul or Tokyo, troubled leaders in both capitals at a time when Trump has increasingly shown his disregard for traditional US allies.

“It suggests that when he’s in the mood, the president will cut deals with our adversaries involving the interests of our allies’’ without consulting them, said Michael J. Green, a former Asia adviser to President George W. Bush who is now at the Center for Strategic and International Studies in Washington.

To some extent, officials in Tokyo and Seoul have grown accustomed to Trump’s seat-of-the-pants decision making, and they also know that not everything he says ends up as official policy.

But at a time when Trump is also going after allies on trade issues, the longer-term worry is that the bonds that have long secured America’s role as a leader in the region are steadily weakening.

A day after the president announced the military drill suspension, defense officials in Washington were still scrambling to determine whether they could soften Trump’s declaration, which directly contradicted past assertions from US military commanders that the joint exercises should not be viewed by North Korea as provocative.

Lieutenant Colonel Christopher Logan, a Defense Department spokesman, said that “we are working to fulfill the president’s guidance.’’

Other officials who spoke on condition of anonymity said that they wanted to hear specifically from the White House just how expansive is the definition of war games.

“Joint exercises are not all war games,’’ said Robert Daly, director of the Kissinger Institute on China and the United States at the Wilson Center in Washington. “This gives Trump room to come back down.’’

Daly said he expected a clarifying statement in the next few days that would say what is, and isn’t, included in the US concession.

The biggest beneficiary of a US withdrawal would be China.

Already, Trump’s preoccupation with North Korea has diverted attention from Chinese actions that alarm its neighbors, most notably a military buildup on islands that China built in the South China Sea.

Ending military drills in South Korea would be a gift to China, which has previously suggested just such a formula: that North Korea freeze its nuclear and missile programs in exchange for a halt to major military exercises by American and South Korean forces.

For China, the ultimate goal is to reduce the US influence in the region as it seeks to consolidate and expand its own power.