Seongnam: A former sex slave for Japanese World War II troops died Sunday at the age of 97, a shelter for the victims said. Lee Ok-seon died at a nursing hospital in Seongnam, just south of Seoul, around 8 p.m. after her health deteriorated.

According to Yonhap News Agency, Lee had been transferred from the shelter to the hospital in March last year. Her death marks a somber moment in the ongoing struggle for recognition and justice for the thousands of women who were forced into sexual slavery during the war.

Historians estimate that up to 200,000 women, mostly from Korea, were mobilized to work in front-line brothels for Japanese soldiers during the war. Korea was a Japanese colony from 1910-45. The House of Sharing in nearby Gwangju, Gyeonggi Province, confirmed Lee's passing and continues to support survivors and advocate for their rights and recognition.