South Korean President Yoon Suk Yeol has told Japanese lawmakers that he is committed to seeking public understanding for Japan's plan to release treated radioactive water into the sea from the crippled Fukushima nuclear power plant, a diplomatic source said Wednesday.

Yoon vowed all-out efforts to remove concerns over the water discharge in his country, "even if it takes time," according to the source.

Former Japanese Prime Minister Yoshihide Suga (L) and South Korean President Yoon Suk Yeol. (Kyodo)

The president, at the same time, called on Japan to provide a more thorough explanation about the safety of the plan during a meeting earlier this month in Tokyo with former Prime Minister Yoshihide Suga and other members of a cross-party group promoting friendly ties with Seoul.

Yoon said in the meeting that he believes that his predecessor Moon Jae In "had avoided efforts to understand," preventing the public from becoming aware of Japan's plan.

The president's pledge is the latest sign of his determination to improve Seoul-Tokyo ties that had long soured over historical issues, including a wartime labor compensation row.

Japan's plan of beginning the water release into the Pacific Ocean sometime from this spring to summer has met firm opposition from such neighbors as China and Russia, warning of a possible impact on the environment. But South Korea's efforts could take some pressure off as Tokyo prepares for the discharge.

The International Atomic Energy Agency has carried out several safety reviews of the plan to ensure the discharge is in line with international safety standards and poses no harm to public health and the environment.

Pacific island nations are also concerned over the treated water, given their suffering of the aftereffects of nuclear tests around their territories by the United States and some European countries in the past.

Public objection in South Korea remains strong, with Seoul maintaining import restrictions on some Japanese food products since the 2011 nuclear disaster at the Fukushima Daiichi plant.

The South Korean president still seeks to gain the public understanding to mend frayed ties with Japan, as cooperation with Japan is even more vital when North Korea is stepping up its missile tests and could conduct its seventh nuclear test anytime soon.

Yoon met with Japanese Prime Minister Fumio Kishida and agreed to work together to normalize relations by resolving major disputes during his first trip to Tokyo since he took office in May last year for two days from March 16.

Prior to the visit, the South Korean government announced a solution to the bilateral dispute over the compensation to former Korean laborers and their relatives for alleged forced labor during World War II under Japan's 1910-1945 colonial rule of the Korean peninsula.

Yoon extended an invitation to Suga, who became the head of the cross-party group on Monday, to his office in South Korea, according to the source.

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