Japan has sought South Korea's understanding of its plan to release treated and diluted water from the crippled Fukushima Daiichi nuclear plant into the sea. Officials reiterated that objective data on the release will be announced quickly.

The director-general of the Japanese Foreign Ministry's Disarmament, Non-Proliferation and Science Department, Kaifu Atsushi, met the head of the South Korean foreign ministry's bureau for climate change, energy, environment and scientific affairs, Yun Hyun-soo, in Tokyo on Tuesday.

Rain and groundwater mixes with water used to cool molten fuel at the Fukushima Daiichi plant. The accumulated water is treated to remove most radioactive substances, but still contains tritium.

Japan's government plans to dilute the treated water to reduce the tritium level. The water released into the ocean will have a tritium concentration about one-seventh the level stipulated in World Health Organization guidelines for drinking water.

Tuesday's talks between the officials, which lasted more than four hours, were based on a summit held by the two countries' leaders in mid-July.

The Japanese side explained that information about the released water will be disclosed quickly and transparently.

Officials added that if any problems occur, such as excessive radioactive materials in the water, the discharge will be halted immediately.

The South Korean side said it respects the report on the matter issued by the International Atomic Energy Agency.

It also said its own assessment confirmed that the discharge would meet international safety standards if carried out as planned.

The South Koreans also asked the Japanese side to conduct effective and transparent monitoring.

The two sides agreed to hold their next meeting as early as next month.

The plan to release the treated water has caused concern among many people in South Korea. The Japanese government says it will continue to offer a thorough explanation of the water release.