Eight lawsuits were filed in South Korea on Thursday seeking compensation from coke producer Nippon Coke & Engineering Co. and three other Japanese companies over wartime forced labor, the plaintiffs' lawyers said.

The remaining three firms named in the suits are Nippon Steel Corp., Mitsubishi Heavy Industries Ltd. and machinery manufacturer Nachi-Fujikoshi Corp. The suits have 31 plaintiffs, including surviving family members of the alleged victims, the lawyers said.

They are the first wartime labor compensation lawsuits to be filed against Japanese firms that involve multiple plaintiffs since the South Korean Supreme Court in October ruled against steel-maker Nippon Steel Corp. over forced labor during World War II.