Japanese Prime Minister Fumio Kishida is considering visiting South Korea in early May to meet with President Yoon Suk Yeol so the countries can further improve ties to address North Korea's ballistic missile program, sources involved in bilateral relations said Friday.

If realized, Kishida's trip to South Korea would be the first by a Japanese premier in five years. Both governments are working on a plan for Kishida to visit on May 7 and 8, the sources said, an apparent bid to promote better relations ahead of the May 19-21 Group of Seven summit in Hiroshima.

Undated photo shows Japanese Prime Minister Fumio Kishida (L) and South Korean President Yoon Suk Yeol. (Kyodo)

Kishida and Yoon agreed to improve Tokyo-Seoul relations, which soured in recent years to the worst level in decades, and visit each other's countries more often during their talks in March in Tokyo.

Japan and South Korea have long been at odds over issues related to Japan's colonial rule of the Korean Peninsula before and during World War II, such as wartime labor for Japanese companies.

Kishida has invited Yoon to the summit of the G-7 industrialized nations and the leaders plan to hold bilateral talks on the sidelines of the gathering in the western Japan city.

The governments of Japan, South Korea and the United States are also arranging a trilateral meeting between Kishida, Yoon and President Joe Biden on the G-7 fringes.

Yoon and Biden agreed to enhance Washington's extended deterrence involving nuclear capabilities against North Korea during their talks in Washington earlier this week.

The last visit to South Korea by a Japanese premier was in February 2018, when then Prime Minister Shinzo Abe attended the opening ceremony of the Pyeongchang Winter Olympics.

Bilateral ties hit their lowest point in decades after South Korea's Supreme Court in 2018 ordered two Japanese firms to compensate Korean plaintiffs for alleged forced labor during Japan's colonial rule of the peninsula.

Yoon took office in May 2022, succeeding President Moon Jae In.

After Seoul proposed in January this year that a foundation backed by the South Korean government pay the money to plaintiffs, Kishida and Yoon confirmed the scheme during their meeting in Tokyo in March.

North Korea has test-launched missiles, including intercontinental ballistic missiles, on nine occasions this year, in defiance of U.N. Security Council resolutions. Fears have also been growing that Pyongyang may carry out its seventh nuclear test in the near future.

On the economic front, Japan said Friday it will put South Korea back on the list of preferred trade partners after a similar move by Seoul for Tokyo's trade status. Japan revoked South Korea's preferential status in August 2019 and Seoul did likewise the following month.