One more South Korean victim of sex slavery for Japan's Imperial Army during the World War II has passed away, leaving the living victims at 49, an advocacy group for the South Korean victims said Thursday.

Kim Yeon-hee, 83, died of natural causes on Wednesday night, the Korean Council for Women Drafted for Military Sexual Slavery by Japan said on its Facebook account.

With her death, the living comfort women victims fell to 49. The comfort women refers to Korean women coerced into sex slavery at Japanese military brothels during the World War II.

Kim was mobilized to an aircraft parts factory in Japan for forced labor in 1944 when she was in her fifth year at an elementary school. After having worked there for nine months, she was taken to the so-called comfort station in Japan to serve as sex slaves for seven months when she was just in her early 10s.

She returned to South Korea as the Korean Peninsula was liberated from the 1910-45 Japanese colonial rule after Japan's surrender in the World War II.

But Kim was treated at a psychiatric hospital and failed to get married as she suffered from a traumatic memory of sex slavery, too harsh for a young girl of her age to bear.

According to historians, at least 200,000 women, mostly Koreans, were deceivably or forcibly mobilized to comfort stations of Japan' s Imperial Army in Japan, China, Southeast Asia and islands of the South Pacific.

Among 238 Korean women who identified themselves as former sex slaves, only 49 are alive as six passed away in 2015 alone.

The comfort women victims and civic group activists have held a rally every Wednesday in front of the Japanese embassy in Seoul since Jan. 8, 1992, calling for apology and reparation from the Japanese government