SEOUL, Dec. 27 (Xinhua) -- South Korea on Wednesday confirmed the existence of a secret deal with Japan in the 2015 agreement between the two countries over the sexual slavery victims of South Korea who were forced into sex enslavement for Japanese military brothels during World War II.

Then South Korean government under ousted President Park Geun-hye agreed with the Japanese government led by Prime Minister Shinzo Abe to persuade South Korean civic groups supporting the victims to accept the 2015 deal and agreed not to assist the erection of a so-called "girl statue" symbolizing the young victims of sex servitude.

The secret deal was not made known to the general public when then foreign ministers of the two countries announced the agreement in Seoul, which was reached on Dec. 28, 2015, a task force team under South Korea's foreign minister said in a 31-page report.

According to the report, the Japanese side demanded South Korea persuade the advocacy groups for the victims to accept the agreement. Then South Korean government pledged to make efforts to prod the groups into actually accepting Japan's demand.

The Japanese side also demanded South Korea not use the word "sex slave." The South Korean side said it used the word "comfort women" in the past, also actually accepting Japan's demand, the report showed.

Comfort women euphemistically refers to the women who were kidnapped, coerced or duped into sexual servitude for Japan's Imperial Army during WWII. Historians say up to 200,000 girls and young women fell victim to the war crime against humanity.

The Japanese side also asked South Korea to remove the girl statue erected outside the Japanese embassy in Seoul. Then South Korean government replied that it will make efforts to appropriately resolve that issue.

The girl statue, which symbolizes the comfort women, was placed in front of the Japanese embassy in Seoul in December 2011 to mark the 1,000th rally demanding Japan's sincere apology and legal responsibility for the wartime atrocity.

Surviving South Korean victims and peace activists have held rally outside the Japanese embassy for more than two decades.

South Korea's governments had maintained a position that it has no right to move the girl statue as it was funded and placed by private citizens voluntarily, but the Park Geun-hye administration agreed with Japan on efforts to remove the girl statue, the task force team said.

The Park government also lacked communications with the victims and failed to get understanding and agreement from the victims, the report said, noting that the 2015 agreement was reached from the government's perspective.

Under the 2015 deal, South Korea and Japan reached a "final and irreversible" agreement on comfort women issues. In return for it, Japan vowed to provide 1 billion yen (about 9 million U.S. dollars) for a foundation dedicated to supporting the sex slavery victims.

The victims harshly protested against it, saying the Japanese government had yet to take its legal responsibility and make a sincere apology for the wartime brutality, and demanded the annulment of the pact.

The new South Korean government under President Moon Jae-in who took office in May said the 2015 deal was not "emotionally" acceptable to South Koreans, ordering a review of the whole procedure in reaching the agreement.