Japanese Prime Minister Fumio Kishida pledged Thursday to bolster relations with his U.S. and South Korean counterparts to address security threats from North Korea, before heading to the United States for their upcoming summit.

Kishida, U.S. President Joe Biden and South Korean President Yoon Suk Yeol are likely to confirm on Friday that their three nations will begin sharing real-time information about North Korea's missile launches at an early date, sources close to the matter said.

"With the security environment becoming more severe, it is of great significance that Japanese, U.S. and South Korean leaders will meet at this time," Kishida told reporters in Tokyo.

"This is a historic move to strengthen the strategic partnership among the three countries based on the unprecedentedly strong bilateral ties with the United States and South Korea," he added.

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

The summit will take place at the Camp David presidential retreat in Maryland. After the trilateral gathering, Kishida, Biden and Yoon are expected to release a joint statement and hold a press conference together.

Kishida is slated to conduct bilateral meetings with Biden and Yoon, respectively, the sources said, adding that the leaders are poised to reaffirm their cooperation in tackling North Korea, which has continued to develop ballistic missiles and nuclear weapons.

Prime Minister Fumio Kishida speaks to reporters at Tokyo's Haneda airport on Aug. 17, 2023. (Kyodo)

The trilateral summit will be the first standalone gathering between the leaders of Japan, the United States and South Korea, as their past discussions were all held on the sidelines of international meetings.

It will also be the first time that Biden, who took office in January 2021, has invited foreign political leaders to Camp David, underscoring the U.S. president's eagerness to deepen relations with his Japanese and South Korean counterparts.

At the summit, Kishida, Biden and Yoon are likely to agree to regularize their gatherings, while vowing to hold annual three-way meetings for the foreign and defense ministers of the three nations, according to the sources.

The leaders may also exchange views on whether the countries will regularly carry out joint drills of their armed forces as well as confirm they will boost ties in fields such as economic security, artificial intelligence and cybersecurity, the sources said.

Moreover, the United States and its close Asian security allies are expected to yield an agreement to set up a hotline for urgent communications between the leaders of the three nations, a senior White House official said Wednesday.

Japan and the United States, meanwhile, are trying to agree at their bilateral summit on jointly developing new interceptor missiles in response to the advancement of hypersonic weapons by North Korea, China and Russia, the sources said.

Kishida and Yoon's meeting comes as Japan prepares to discharge treated radioactive water from the disaster-stricken Fukushima nuclear power plant into the Pacific Ocean, but the South Korean presidential office said the issue will not be discussed during the bilateral meeting.

The Japanese premier is scheduled to return to Tokyo on Saturday, government officials said.

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