HARBIN - Seven files related to comfort women were made public Tuesday by a record office in Heilongjiang province, Northeast China, the latest evidence to support allegations that Japan used women as sex slaves during World War II.

"Evidence proves that Japanese forces forcibly recruited and coerced Chinese and Korean women to be sex slaves for the Japanese Imperial Army during the war," said Qi Xiujuan, head of the Heilongjiang Archive.

"These files further support these accusations [...] and they will aid research into the comfort women issue," Qi said.

An estimated 200,000 women were forced into sexual servitude in China during WWII, but only a handful are still alive, of which many have admitted publicly that they were used as comfort women. Thousands took their secret to the grave without receiving an apology or compensation from the Japanese government.

The seven files include evidence that there were several Japanese-run comfort woman stations in the province in 1941 and 1942, and they had been run by the military police.

One of the files, dated October 1941, outlined plans for a comfort woman station in Suifenhe City that required "about 10 women to serve about 2,000 Japanese soldiers". It went on to say that "ordinary soldiers could be entertained for half an hour, and the time will extend to one hour for high-ranking officers".

"The practice is a violation of women's rights, and it exposes the cruelness of the Japanese forces," Qi said.

The files are opened to Chinese citizens and foreign organizations or individuals for research.