South Korea and Japan held 12 hours of working-level talks to discuss details of Seoul's dispatch of a team of experts to inspect Tokyo's planned release of wastewater from the Fukushima nuclear power plant, but failed to peg down how and when the inspection will take place.

Seoul's foreign ministry said Saturday the two sides agreed to have the team visit Japan for four days. The two sides will hold an additional meeting soon to iron out details such as its schedule and the scope of its activities.

The ministry said both sides sincerely and proactively took part in the talks which continued past midnight. It said that extensive discussions focused on the timetable of the visit and the scope of the team's activities in Japan.

The talks, which began at the foreign ministry building in Seoul at 2 p.m. Friday, were expected to last for four to five hours but continued for 12 and ended at around 2 a.m. Saturday.

The two sides have been at odds over the role of the inspection team. Seoul says its activities will be close to a verification while Japan has balked at the idea. In the latest talks, they apparently clashed over the purpose of the inspection, to which facilities they would have access and what information the Korean team would receive.

In a Friday briefing, first vice minister of government policy coordination Park Ku-yeon said the government is seeking to have the team check on the overall operation of related facilities and Tokyo's capacity to analyze radioactive materials and gather information necessary for South Korea's own scientific and technical analysis.