A skull believed to be one of the victims of the 1942 Chosei undersea coal mine disaster has been recovered from the site in Yamaguchi Prefecture, Japan.

Tuesday’s find comes a day after thigh bones and other remains were pulled from the water at the site, where 136 Korean forced laborers and 47 Japanese died in a flooding accident during the Japanese colonial period.

Korean and Japanese civic groups leading the probe said further remains could be present but conditions inside the submerged tunnels are too murky to confirm.

The groups urged Seoul and Tokyo to establish a joint mechanism to recover, identify and return victims’ remains, saying civic efforts alone have reached their limit.

Japan’s government has so far refused to provide support, citing unclear burial locations and safety risks, with Health Minister Takamaro Fukuoka reiterating Friday that no new funding is planned.

The Chosei tragedy remains one of the deadliest episodes of forced labor under Japan’s colonial rule, with survivors’ families still awaiting a full investigation and repatriation.