Osaka Mayor and Nippon Ishin no Kai (Japan Restoration Party) coleader Toru Hashimoto refused Wednesday to back down from his comments about the necessity of the "comfort woman" system during the war or the desirability of legal brothels in Okinawa for U.S. military personnel.

Hashimoto's views, originally aired Monday, have created a firestorm in and out of Japan, with ruling and opposition party politicians rushing to distance themselves from him and concern within Nippon Ishin that the controversy will spark a backlash in this summer's Upper House election, assuming the party is still intact when it takes place.

Speaking to reporters in Osaka shortly after Prime Minister Shinzo Abe told an Upper House committee that Hashimoto's position on the issue of wartime sex slaves is different from that of the ruling Liberal Democratic Party, the Osaka mayor said the comfort women issue was settled in a 1965 treaty with South Korea.