South Korean President Yoon Suk-yeol on Friday called for Japan to conduct a scientific analysis before releasing treated radioactive water into the sea from the crippled Fukushima nuclear power plant, Japanese lawmakers said.

With concern lingering about the impact of the treated water on the ocean environment, Yoon's remarks came during a meeting with former Prime Minister Yoshihide Suga, the soon-to-be new head of a cross-party group of lawmakers promoting friendly ties between Tokyo and Seoul.

Suga was quoted by lawmakers as telling Yoon, who became the first South Korean president to visit Japan in four years on Thursday, that the government has "proceeded with the plan" to discharge the treated water in conjunction with the International Atomic Energy Agency.