China will work with South Korea in urging Japan to understand and reflect on history regarding the issue of “comfort women,” who were coerced into sex slavery by Japanese forces during World War II.

Chinese foreign ministry spokesperson Hong Lei made the comment on Thursday in response to a South Korean plan to apply to register records with UNESCO on Japan’s wartime sex slaves.

Forcing women into sexual slavery was a grave crime against humanity by the Japanese military during WWII, causing suffering in China, South Korea and some other Southeast Asian countries, Hong said.

China and South Korea have similar experiences and concerns on historical issues relating to Japan, Hong said.

“China is willing to work with other victim countries, including South Korea, to maintain historical justice,” Hong said, adding that Japan should work to gain the trust of its neighbors and the international community through concrete action.

South Korea’s Ministry of Gender Equality and Family plans to examine and archive relevant materials scattered in the victim countries and apply next year, in order to get Japan’s use of wartime sex slaves registered at UNESCO’s Memory of the World program, the Yonhap News Agency reported.

The Memory of the World program was launched in 1992 to preserve heritage around the world.

The US House of Representatives on Wednesday passed a spending bill in which a document is attached, calling on Secretary of State John Kerry to encourage Japan to address the issue of “comfort women,” the contemporary euphemism for sex slaves.

The document referred to Resolution 121, which was adopted by the house in July 2007, calling for Japan to “formally acknowledge, apologize and accept historical responsibility in a clear and unequivocal manner.”

South Korea on Thursday welcomed the house’s call for Japan to apologize to the coerced sex slaves, while a foreign ministry spokesman said that there was little time left for Japan to resolve the issue.

Historians estimate that 200,000 women were forced into sexual servitude by Japanese forces during WWII, most from countries invaded by Japan at the time.