US Defense Secretary Lloyd Austin will hold a trilateral meeting with his Japanese and South Korean counterparts in Tokyo on Sunday local time, the first of its kind in 15 years, a senior US defense official said.

The trilateral meeting came nearly one year after President Joe Biden held the first stand-alone summit with Japanese Prime Minister Fumio Kishida and South Korean President Yoon Suk Yeol at Camp David in August 2023. Following the summit, Kishida announced that annual recurring summits will be held among several of the nations’ highest officials, including the ministers of foreign affairs, defense, and national security advisers, along with the financial, industry, and commerce ministers.

“We’ve made enormous progress, trilateral since the Camp David summit, with early warning missile data sharing real time with a trilateral exercise plan,” the US senior defense official said.

According to the defense official, Secretary Austin is expected to announce the US intends to reconstitute US Forces Japan (USF-J) as a joint force headquarters to serve as a counterpart to Japan’s Joint Operations Command (J-JOC). Details of this implementation will be figured out in working groups led by US Indo-Pacific Command. There is no intention to integrate Japanese forces into the US commands, according to the official.

“The intent here is for USF-J to become a standalone three-star joint force headquarters. Eventually separate and apart from 5th Air Force,” the official said.

“We view this as a historic announcement among the strongest improvements to our military ties in 70 years. Bottom line is that this is a transformative change. And that’s because when this transition is complete, USF-J will have a direct leadership role in planning and leading US forces in both peace time and potential crises. And they’ll be doing that side by side with Japanese forces like never before.”