Japan, the United States, and South Korea are expected to agree during their upcoming leaders meeting near the U.S. capital to hold annual three-way gatherings for their foreign ministers and defense ministers, respectively, diplomatic sources said Wednesday.

In the latest sign of strengthening ties between the three countries, Japanese Prime Minister Fumio Kishida, U.S. President Joe Biden and South Korean President Yoon Suk Yeol are already planning to agree on Friday when they meet in Camp David to hold trilateral summits at least once a year.

The move comes as the three nations seek to ramp up collaboration to address North Korea's missile and nuclear threats and China's assertive military activities in the Indo-Pacific region and growing economic clout.

Combined photo shows (from L)  U.S. President Joe Biden, Japanese Prime Minister Fumio Kishida and South Korean President Yoon Suk Yeol. (Kyodo)

According to the sources, the three countries are also seeking regular meetings between senior officials in charge of national security.

They are also considering setting up three-way, working-level consultative bodies on issues such as artificial intelligence, economic security and cyber security, the sources said.

Friday's gathering marks the first standalone summit between the three leaders, as their previous talks were typically held on the fringes of international meetings. Despite a bitter wartime history that has frequently divided Japan and South Korea, their relations have significantly improved since Yoon assumed office last year.