U.S. Forces Korea troops participate in a joint exercise with Korean troops in Paju, Gyeonggi Province, Monday, during the Korea-U.S. joint Freedom Shield exercise. Yonhap

The Donald Trump administration's reported decision to scrap a planned buildup of American forces in Japan has left Seoul concerned about the potential implications for U.S. Forces Korea (USFK).

Analysts said Friday that while an immediate impact on USFK is unlikely, Trump's stance of cutting defense expenditures and pressuring allies to do more could complicate future negotiations with Korea over the stationing of 28,500 U.S. troops.

According to CNN, the Pentagon is considering substantial budget cuts, including consolidating combatant commands, scaling back education programs for the joint force and halting the expansion of U.S. Forces Japan (USFJ). The suspension of this expansion is expected to save approximately $1.18 billion, reports said.

These reports, if true, would mark a significant U-turn of U.S. pledges on alliance integration with Japan and could have an impact on neighboring Korea as well.

But Chun In-bum, a former Korean Army lieutenant general and ex-commander of the Special Warfare Command, said an immediate impact on American troops in Korea is unlikely.

He said the CNN report "summarizes the potential significant impact of the U.S. defense policy under the new Trump administration," but noted that it "has no mention of USFK."

"Although this does not mean USFK will not be impacted directly or indirectly by these policies, for the moment, USFK is focused on the maintenance of stability in Northeast Asia. For Korea, we must be a more capable ally to the U.S.," he told The Korea Times.

He also emphasized that the Trump administration's decision to cut overall defense spending by 8 percent annually signals major changes, which could have both direct and indirect impacts on Korea.

In February, Defense Secretary Pete Hegseth said the Pentagon will pull 8 percent — or roughly $50 billion — from nonlethal programs in the current budget and refocus that money on the Trump administration's "America First" priorities for national defense. This was part of the department's plan to slash 8 percent of its budget each year for the next five years.

Earlier this week, Hegseth announced another $580 million worth of cuts, bringing the total money saved to $800 million since his February announcement, according to the U.S. Department of Defense.

U.S. President Donald Trump prepares to sign an executive order aimed at downsizing the Department of Education in a ceremony at the White House in Washington, Thursday (local time). UPI-Yonhap

Kim Yeoul-soo, an analyst at the Korea Institute for Military Affairs (KIMA), also projected that USFK would not be immediately affected by U.S. defense plans for Japan.

"If these reports are accurate, it seems Trump is focused more on reversing his predecessor's initiatives and cost-saving promises with allies. So I don't expect immediate impact for the U.S. troops stationed in Korea," Kim said.

In 2024, the Joe Biden administration and then-Japanese Prime Minister Fumio Kishida's Cabinet agreed to upgrade USFJ into a joint force headquarters with expanded missions and operational responsibilities, including the possibility of deploying a four-star commander to the country.

"Trump may not see this plan as essential as long as USFJ continues to function as a key front-line ally in the region," Kim said.

"It's unclear what Trump's broader policy will be toward Asian alliances, but one thing is certain: he wants to use Korea and Japan to counter China," the analyst said. "Trump has not yet commented much on USFK or Korea-related policies, so it's too early to determine his stance. But as his defense officials and aides have noted, the Trump administration wants to keep China in check by using its forces in Korea."

Still, analysts believe that the defense cost-sharing issue could become a source of tension in bilateral relations during Trump's term.

During his first term, Trump demanded that Seoul increase its share of defense costs from $900 million to $5 billion, a move that strained the bilateral alliance. He has consistently argued that Korea, as a wealthy nation, is not contributing enough toward its own defense.