The U.N. human rights chief vowed to “advocate” for the victims of Japan’s wartime sexual slavery Wednesday as he met with three Korean victims in Seoul, who have long demanded that Tokyo take legal responsibility for the atrocities.

U.N. High Commissioner for Human Rights Zeid Ra‘ad Al Hussein met Kim Bok-dong, Gil Won-ok and Lee Yong-soo, who were forced by Japan to serve at frontline military brothels during World War II, during his visit to a museum on women’s wartime human rights in central Seoul.

“I will of course stay in touch with them and visit them again as often as I can,” he said, stressing that his organization will continue to advocate on their behalf.

Zeid came to Korea on Tuesday for a three-day visit to attend the ceremony to launch a U.N. field office to systematically monitor and study North Korea’s human rights situation.

His support for the victims, euphemistically called “comfort women,” came as Seoul and Tokyo have engaged in intense talks over the issue of the victims, which Seoul believes is a wartime human rights issue that goes beyond the bilateral relationship.

The two sides have held eight rounds of director-general-level talks since April 2014. President Park Geun-hye recently told The Washington Post that there has been “considerable” progress in the negotiations and the talks are in the “final stage.”

Seoul has demanded that Tokyo offer an explicit apology and take legal responsibility to compensate the victims. But Tokyo has argued that all colonial-era issues were settled in a 1965 pact that normalized the bilateral relations.

By Song Sang-ho (sshluck@heraldcorp.com)