SEOUL (Reuters) - South Korea's top court ruled on Thursday that Japan's Mitsubishi Heavy Industries Ltd 7011.T must compensate 10 South Koreans for their forced labor during World War Two, a ruling that drew an immediate rebuke from Tokyo.

The decision echoed the Supreme Court's landmark verdict last month that ruled in favor of South Koreans seeking compensation from Japan's Nippon Steel & Sumitomo Metal Corp. 5401.T for their wartime forced labor.

It upheld a 2013 appeals court decision that Mitsubishi must pay 80 million won ($71,000) to each of five laborers or their families in compensation.

In a separate ruling, the court also ordered Mitsubishi to pay up to 150 million won to each of another five plaintiffs or their families.

Mitsubishi called the verdict “deeply regrettable”, saying in a statement that it would discuss its response with the Japanese government.

Japan and South Korea share a bitter history that includes Japan’s 1910-45 colonization of the Korean peninsula and the use of comfort women, Japan’s euphemism for girls and women, many of them Korean, forced to work in its wartime brothels.

The rows over wartime history have long been a stumbling block for relations between the East Asian neighbors, sparking concern that it could jeopardize joint efforts to rein in North Korea’s nuclear program.

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Japanese Foreign Minister Taro Kono issued a statement calling the court’s decisions “totally unacceptable”. The ministry summoned the South Korean ambassador to lodge a complaint.

“The decisions completely overthrow the legal foundation of the friendly and cooperative relationship” between the two countries, Kono said.

Kono urged Seoul to take immediate action to remedy “unjustifiable damages and costs” inflicted on Japanese firms or Tokyo would consider its options, including referring the case to an international court.

South Korea’s Foreign Ministry expressed regret over what it called Japan’s “extreme reaction”, also calling in the Japanese ambassador and urging restraint.

“We will craft our response in a way that could heal the victims’ pain and wounds, but at the same time foster a forward-looking relationship with Japan,” ministry spokesman Roh Kyu-deok told a news briefing.

“But the administration has to respect a judiciary decision under the principle of the separation of the powers.”

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Previous cases the group of five former laborers had brought in Japan were dismissed on the grounds that their right to reparation was terminated by a 1965 treaty normalizing diplomatic ties between Seoul and Tokyo.

However, the South Korean Supreme Court upheld last month’s ruling that Japan’s occupation of the peninsula was illegal.

“The treaty does not cover the right of the victims of forced labor to compensation for crimes against humanity committed by a Japanese company in direct connection with the Japanese government’s illegal colonial rule and war of aggression against the Korean peninsula,” the court said in a statement.

Kim Seong-ju, a 90-year-old plaintiff in the second case, said she was sent to Japan when she was 15 with the recommendation of her teacher, who was a Japanese national.

“I was told that I could go to middle and high school and study more, but it turned out I had to work at the factory all the time,” Kim told a news conference after the ruling, showing her permanently injured hand. “Now I feel great.”