SEOUL, Jan. 4 (Xinhua) -- South Korean President Moon Jae-in on Thursday invited the victims of Japan's sex slavery during World War II to the presidential Blue House, apologizing for the 2015 agreement over the victims between South Korea and Japan.

President Moon met with eight surviving comfort women victims and had lunch together at the presidential complex after the Moon government's review result over the 2015 agreement revealed secret deals between the two countries, according to the Blue House.

During the meeting, Moon apologized for the agreement reached on Dec. 28, 2015, as it dismissed the will of the victims.

The 2015 deal was reached by the previous South Korean government, but Moon apologized for it as the country's incumbent president.

The surviving victims expressed their gratitude for Moon's efforts to disclose the secret deals, saying they demanded the Japanese government's sincere apology and legal responsibility for the wartime crime against humanity.

The review report disclosed secret deals between the previous South Korean government and the Japanese cabinet led by Prime Minister Shinzo Abe, such as Seoul's acceptance of Tokyo's demand for persuading the victims to favor the 2015 agreement and not using the word of "sex slaves."

Comfort women euphemistically refers to Korean women who were kidnapped, forced or duped into sex servitude for Japanese military brothels during the Pacific War. Historians said up to 200,000 girls and young women, mostly from the Korean Peninsula, served as sex slaves for the Imperial Japan.

Following the announcement of the review result, Moon said the sex enslavement issue cannot be resolved by the 2015 deal, in which Seoul and Tokyo reached the final and irreversible agreement to the issue in return for Japan's offer of 1 billion yen (9 million U.S. dollars) to a foundation supporting the victims.