Osaka Mayor and Nippon Ishin no Kai (Japan Restoration Party) co-leader Toru Hashimoto remained defiant Wednesday in the face of a fresh round of domestic and international criticism over his comments that Japan's wartime "comfort women" system of sex slavery was necessary at the time.

On Tuesday, the 11-member San Francisco Board of Supervisors, the city's legislative branch, unanimously adopted a resolution demanding Hashimoto retract his comments and calling on San Francisco Mayor Edwin Lee, in his capacity as mayor of Osaka's sister city, to send the petition to Hashimoto and the Osaka Municipal Assembly. The resolution will also be sent to U.S. President Barack Obama, Secretary of State John Kerry and members of Congress.

"The board of supervisors strongly condemns the attitude and statements of Hashimoto justifying the state-sponsored 'comfort women' system, which forced hundreds of thousands of Asian women into sexual servitude for the Japanese military, and denying the historical veracity of such atrocities committed against women and girls in countries occupied by Japan throughout East and Southeast Asia."