China on Wednesday rejected a call by Japan to drop its bid to have documents related to Japan's sexual enslavement of Asian women during World War II added to the UNESCO world memory list, calling the Japanese request "unreasonable."

The reaction by Japan came a day after China confirmed that it has submitted the documents for inclusion in UNESCO's Memory of the World Register to prevent such crimes against humanity from happening again.

Japan's chief government spokesman, Yoshihide Suga, told reporters in Tokyo that his government lodged a protest and asked China to withdraw the application to the U.N. body.

Asked about the Japanese reaction, China's foreign ministry spokeswoman Hua Chunying said the application is "to memorize the history, treasure the peace, uphold the dignity of mankind and prevent behaviors against humanity, human rights and human beings from happening again."

"We will not accept the unreasonable request from Japan and we will not withdraw the application," Hua said.

Historians say up to 200,000 women from Korea, China and other Asian nations were coerced into sexual servitude at front-line Japanese brothels during the war. Those sex slaves were euphemistically called "comfort women."

Japan's nationalist politicians, including Prime Minister Shinzo Abe, have drawn criticism by arguing that there is no evidence that the women were coerced by the then Japanese government.

South Korea has also pressed Japan to address long-running grievances by the victims of wartime sex slavery by extending a formal apology and providing them compensation. But Japan has refused to do so, saying the matter was settled by a 1965 treaty that normalized relations between the two countries.

Time is running out for those aging victims in South Korea. On Sunday, a 91-year-old South Korean victim, Bae Chun-hee, died. Currently, only 54 victims remain alive in South Korea and their average age is 88. (Yonhap)