OSAKA, June 26 -- A group of 13 Chinese former World War II forced laborers and their relatives filed a lawsuit with the Osaka District Court on Friday, seeking apologies and compensation of 5.5 million yen (about 44,500 U.S. dollars) per victim from the Japanese government.

Among the 13 plaintiffs, nine are survivors and relatives of forced laborers killed in an uprising that occurred at Hanaoka mining camp in Japan's Akita Prefecture in 1945, which later came to be known as "the Hanaoka Incident."

On June 30, 1945, about 700 Chinese forced laborers at the Hanaoka mining camp staged an uprising. Over the following three days, over 130 Chinese were tortured and killed by Japanese army and police.

From 1944 to 1945, about 986 Chinese forced laborers were forced to toil at Hanaoka mine. More than 400 of them died there from malnutrition, illness, physical abuse and plain murder, including those killed in the uprising.

87-year-old Zhang Guangxun is a survivor of the Hanaoka Incident. He was sent to the Hanaoka camp at the age of 16. "I can never forget those days. I hope the Japanese government could apologize to the victims and show true remorse. Only by doing that could they gain forgiveness from the Chinese people," he told a press conference held on Friday.

Han Jianguo, son of another forced laborer at Hanaoka camp, showed photos of the miserable forced laborers at Hanaoka camp. " These photos were taken when the forced laborers were rescued in 1945 by the U.S. Army. They were stored in the archives of the United States and are precious historical evidence."

"About 40,000 Chinese were kidnapped and forced to work under harsh conditions in Japan during WWII. At least 6,830 of them died in Japan from torture and physical abuse. But till now, the Japanese government still refuse to apologize to the forced-labor victims. We hope the Japanese government could acknowledge the history and show true remorse. That's why we file this lawsuit," Han said.

The Japanese government claims that the 1972 joint statement that normalized relations with China denies all rights to seek reparations for wartime offenses. But Chinese legal experts believe that individuals' rights to pursue legal action were not renounced by the statement.