SEOUL : Japanese Prime Minister Fumio Kishida said Sunday that his "heart aches" over South Korea's colonial-era suffering, as he hailed fresh efforts to mend Tokyo's long-strained ties with Seoul at a landmark summit.

"My heart aches as many people went through a very difficult and sad experience in the harsh environment at that time," Kishida said, speaking after a summit with South Korean President Yoon Suk Yeol.

The East Asian neighbours, both crucial security allies of the United States, have long been at odds over historic issues linked to Japan's brutal 1910 to 1945 colonial occupation of the Korean peninsula, including sexual slavery and forced labour.

The two countries have been locked in a tit-for-tat economic dispute since 2018, when South Korea's Supreme Court ordered Japanese firms to compensate the wartime victims of forced labour, enraging Tokyo.

But Yoon, who took office last year, has sought to bury the historical hatchet, earlier announcing a plan to compensate victims without direct involvement from Tokyo.

The move was unpopular domestically, including with victims who say it stops short of their demands for a full apology and compensation from the Japanese companies involved.

Seoul says many of the victims have since accepted the deal.

Experts had predicted Tokyo would not offer a new apology, and Kishida stopped short of this, instead reaffirming the "heartfelt apology" made by previous administrations in Tokyo.

"When President Yoon visited Japan last March, I made it clear that I was inheriting the position of the previous cabinets related to recognising history," Kishida said, saying he stood by a 1998 agreement which included an apology for colonial era woes.

"This government position will not be shaken in the future," he said.

Yoon has said repeatedly that the two countries need to settle their historical disputes, telling AFP in March that it was long overdue that the two countries "end the vicious cycle of mutual hostility and work together" to improve regional security.

Kishida said it was his "responsibility as the prime minister of Japan to inherit and continue the efforts of our predecessors who overcame difficult times and cooperate with the South Korean side, starting with President Yoon, to cooperate toward the future".