Tuesday’s U.S.-North Korea summit was hailed as a diplomatic breakthrough, but it unleashed critical security concerns around Asia.

By questioning America’s military presence in the region, President Donald Trump on Tuesday appeared to give his Asian allies the cold shoulder while delivering a huge win to Pyongyang and Beijing.

At the conclusion of the U.S.-North Korea summit, the president announced a halt of what he called “provocative” and “expensive” war games — drills that the U.S. and South Korean armies have jointly conducted for years. Trump also indicated a desire to remove the 32,000 U.S. soldiers currently stationed in South Korea.

“I’d like to be able to bring them back home … That’s not part of the equation right now. At some point, I hope it will be, but not right now,” he said at a press conference.

Those comments sparked “a clear sense of disappointment” among Asia-watchers, according to Sam Roggeveen, a senior fellow at the Lowy Institute: “Trump made a major concession by pledging to stop joint military exercises,” but “got less from Kim Jong-un than Bill Clinton got from North Korea.”

America’s security alliance with South Korea is a crucial element of Washington’s greater Asia presence. That strategic relationship, according to U.S. Defense Secretary James Mattis, is the linchpin of peace in the Asia Pacific region and is widely considered critical to the safety of not just Seoul, but Tokyo, Taipei and others.

That’s why Trump’s Tuesday concessions are massively concerning to North Asia. They trigger immediate questions about the region’s own defense preparedness and the possibility of diminished ties with the world’s largest economy, according to Scott Seaman, Asia director at political consultancy Eurasia Group.

China, however, may have seen its position improve from the summit.

A suspension of war games and U.S. troop withdrawal in South Korea not only caters to Pyongyang, which has long demanded both as prerequisites for denuclearization, they are also highly beneficial to Beijing. The world’s second-largest economy has long sought to prevent U.S. influence in its backyard and widen the gap between Washington and its allies, experts said.

South Korea and Japan expressed surprise at Trump’s statements following the summit.

“At this point, we need to know President Trump’s exact meaning or intentions,” said the Blue House, South Korea’s equivalent of the White House. Meanwhile, Japanese Defense Minister Itsunori Onodera said the U.S.-South Korea drills were “vital” to East Asia, adding that his country wished to “seek an understanding of this between Japan, the U.S. and South Korea.”

That kind of reaction “speaks volumes about the degree to which this outcome was coordinated with partners,” said Evans Revere, nonresident senior fellow at the Center for East Asia Policy Studies at think tank Brooking: “I suspect that America’s Asian allies are shuddering right now.”

In an effort to curb fears, South Korean Foreign Minister Kang Kyung-wha said on Thursday that the U.S.-South Korean alliance remains as “robust as ever.” American forces in the country “play and will continue to play a crucial role in deterrence, peace and stability on the Korean Peninsula,” she continued.

Going forward, South Korean President Moon Jae-in and Japanese Prime Minister Shinzo Abe “will insist on having a say in how Trump’s pledge to halt military exercises is operationalized,” Seaman continued.

Beijing, on the other hand, likely welcomed the development.

“Stopping the joint exercises has been a long-term goal for North Korea and China. Trump delivered it while getting nothing in return beyond the same generalities that North Korea has been offering since the early 1990s,” Victor Cha, a Georgetown University professor and senior advisor at the Center for Strategic and International Studies, said in a note.

One analyst identified a way for the White House to keep the joints drills with Seoul while still placating the North Koreans, who view the annual event as a threat to national security.

The logical thing parties may settle on is “the removal of strategic assets from these exercises — B-1 bombers and B-2s — that show good faith and show the U.S. is engaging in exercises that are for defense, not offensive purposes,” said Daryl Kimball, executive director of the Arms Control Association.