South Korea's rival political parties demanded Monday that the new chairman of Japanese public broadcaster NHK resign for denying any wrongdoing in Japan's recruitment of Korean women as sex slaves during World War II.

The issue of the so-called "comfort women" has long been a thorn in relations between South Korea and Japan as Tokyo has snubbed Seoul's demands for talks on compensating the aging Korean women.

Historians say up to 200,000 women, mostly Koreans, were coerced into sexual slavery at front-line Japanese military brothels during Tokyo's 1910-45 colonial rule of the Korean Peninsula.

Speaking at a news conference Saturday, Katsuto Momii, the new NHK chairman, claimed that the practice existed in "every country" and that it is only considered wrong by "today's morality."

The matter is complicated because South Korea says Japan was the only country that forcibly recruited such women, he said, adding that all compensation was settled under a 1965 treaty that normalized ties between the two countries.

His remarks have angered South Korea especially following the death of a 90-year-old former sex slave on Sunday.

South Korea's ruling Saenuri Party expressed condolences over the death of the victim, Hwang Kum-ja, and vowed to make utmost efforts to receive an apology from Japan.

"Japan must bear in mind that it will forever go down in history as an unapologetic perpetrator when all the victims pass away," Hwang Woo-yea, the chairman of the ruling party, said at a Supreme Council meeting.

Lee Hye-hoon, a member of the Supreme Council, also expressed her grievances.

"It breaks my heart to think that the last remarks (Hwang) heard from a high-ranking Japanese official were the reckless remarks of the NHK chairman," she said.

"The chairman should immediately apologize to the South Korean people and step down from his post, while Japan -- if it still has a conscience -- should be ashamed by the fact that such a person is the chief of a public broadcaster and get him to resign."

The main opposition Democratic Party also voiced anger at Momii's remarks.

"The more the reckless remarks continue, the clearer it will become that Japan is still no more than a nation of war crimes," DP chairman Kim Han-gil said at a meeting of the party's Supreme Council. (Yonhap News)