US Secretary of State Mike Pompeo is set to hold talks on Tuesday with counterparts from Australia, India and Japan in Tokyo.
The “Quad meeting” comes as all four countries seek to form a front against an increasingly assertive China.
Bilateral ties between the US and China have in recent months plummeted to their lowest point in decades.
Washington has moved to boost cooperation with regional allies in the face of Chinese dominance.
The Quad group – represented by Japan’s Toshimitsu Motegi, Australia’s Marise Payne and India’s Subrahmanyam Jaishankar – is expected to discuss issues including the coronavirus pandemic and cyber security.
Before he left the US, Mr Pompeo told reporters the meeting was “something we’ve been working on for a long time to put together”.
“Looking forward to discussing increased cooperation to promote our shared vision for a free and open #IndoPacific, composed of nations that are independent, strong, and prosperous,” he tweeted on departure.
China had warned ahead of the meeting against “exclusive cliques” that target third-parties.
“We hope relevant countries can proceed from the common interests of countries in the region, and do more things that are conducive to regional peace, stability and development, not the other way around,” AFP quoted the Chinese foreign ministry spokesman Wang Wenbin as saying.
The first Quad meeting took place in New York last year – though the group is not a formal alliance. (BBC)