SEOUL, July 1 (Xinhua) -- South Korea's Minister of Trade, Industry and Energy Sung Yun-mo said Monday that his country will file a suit with the World Trade Organization (WTO) over Japan's export restrictions on materials key to South Korea's tech industry.

Sung said in a statement that South Korea will take necessary measures, including the lawsuit with the WTO, based on domestic and international laws.

Sung expressed a deep regret over Japan's export curbs, which he called an economic retaliation over the South Korean top court's rulings over some Japanese companies to compensate the South Korean victims of forced labor during World War II.

Japan announced its plan earlier in the day to impose export restrictions from Thursday on three materials necessary to manufacture semiconductors and display panels, which are vital to South Korea's tech industry.

The materials are fluorinated polyimide used to make flexible display panels, hydrogen fluoride used to etch chips and display panels, and polymer resist used both for chips and display panels.

It came about eight months after the South Korean top court ordered Nippon Steel, which changed its name from Nippon Steel & Sumitomo Metal Corp. earlier this year, to compensate four forced labor victims.

A Seoul appellate court passed a similar judgement last week, upholding the lower court's order to the Japanese steelmaker to pay compensation to the family members of seven South Korean forced labor victims who already passed away because of old age during the trial for the past six years.

The South Korean top court also ruled that Mitsubishi Heavy Industries Ltd. must compensate two groups of forced labor victims, while other Japanese companies, including Nachi-Fujikoshi Corp. and Mitsubishi Materials Corp., were also sued by additional South Korean victims.