Three women forced to work in Japan's wartime military brothels have been speaking out about their ordeals, saying the world should never forget what they went through.

In recent interviews, the Indonesian, Filipina and Korean women repeated that they were the victims of systematic abduction and sexual slavery conducted by Imperial Japanese soldiers, despite counter-claims from some quarters in Japan itself.

"The most important thing is the stories of the victims themselves. The Japanese government should listen to my story and investigate the matter," said 85-year-old South Korean Lee Yong Soo, who has become a symbol of the sex slaves in Korea — a group euphemistically known in Japan as the "ianfu," or "comfort women."