Japan has reacted strongly to a move by South Korean victims of forced labor to seize the assets of a Japanese firm implicated in wartime crimes. 

Japan’s Chief Cabinet Secretary Yoshihide Suga said in a regular media briefing on Tuesday that the Japanese government considers the situation to be “very serious."

On Monday, legal representatives of the South Korean victims announced a plan to seize Mitsubishi Heavy Industries’ assets within South Korea, including those regarding its brands and patents, at an early date. The move came as the company refused to comply with their request to talk about compensation. 

The Japanese minster called the plan a violation of a 1965 normalization treaty, and stressed Tokyo has repeatedly demanded formal talks with Seoul over the issue. He argued the Japanese government believes the South Korean government will sincerely respond.  

Suga refused to elaborate on what additional measures Tokyo will take but said they will properly respond to protect the economic activities of Japanese firms.

Late last year, the South Korean Supreme Court ruled in favor of dozens of Korean forced labor victims against Mitsubishi Heavy Industries and Nippon Steel & Sumitomo Corporation. 

The plaintiffs in the case involving Nippon Steel already filed a suit to seek the seizure of the company’s asset in South Korea, which a court in Pohang granted in January.