A former sex slave for Japanese troops during World War II has died, a civic group said Thursday, bringing the total of living South Korean victims to 49.

Kim Youn-hee died of natural causes at a hospital in Seoul on Wednesday, the Korean Council for the Women Drafted for Military Sexual Slavery by Japan said. She was 83.

Kim, who was born in 1932, was forced to work in a factory in Japan at age 12 and then transferred to a military brothel. She came back home after Korea was freed from the 1910-45 colonial rule but lived the rest of her life at a mental institution.

Her death leaves only 49 South Korean surviving victims of one of the most serious wartime crimes by Japan. Initially, 238 women were on the list of government-registered former sex slaves.

Historians say more than 200,000 women, mostly Koreans, were coerced into sexual slavery at front-line Japanese military brothels during the colonial era.

South Korea has urged Japan to resolve the grievances of the victims, saying the issue is becoming increasingly urgent as most victims are elderly, well over 80 years old, and may die before they receive compensation or an apology from Japan.

Japan has snubbed Seoul's demand for official talks on compensating the aging Korean women, claiming all issues regarding its colonial rule were settled in a 1965 package compensation deal under which the two countries normalized their relations. (Yonhap)