A South Korean woman who was forced into sexual slavery for the Japanese imperial army during World War II died Sunday, a civic group said, another sign that time is running out for the aging victims to receive an apology and due compensation.

Bae Chun-hee died at the age of 91, according to the House of Sharing, which runs a shelter for victims of Japan's sexual enslavement.

Her death leaves only 54 surviving victims of one of the most serious wartime crimes by Japan. Initially, 237 women were on the list of government-registered former sex slaves.

Historians estimate that up to 200,000 women, mainly from Korea and China, were forced to work at front-line brothels for Japanese soldiers during the war. The victims are euphemistically called "comfort women."

Many of the women, now elderly, have already died, increasing the worry that the remaining victims may also pass away before Japan admits to its wrongdoings and makes atonements.

Last month, South Korea and Japan held a second round of talks on the comfort women issue following their agreement in April to hold such meetings on a regular basis.

South Korea demands that Japan show sincerity by settling the issue "effectively and in a way that is agreeable to the living victims," including through an apology and compensation.

Japan had long dismissed Seoul's demands, claiming that all grievances related to its 1910-45 colonial rule of the Korean Peninsula were settled through a 1965 treaty that normalized their bilateral ties. (Yonhap)