An outspoken politician who drew ire for defending the use of sex slaves during wartime firmly stood by his remarks but said he may have been “insensitive”.

Osaka Mayor Toru Hashimoto refused to apologize for his comments on “comfort women” and instead acknowledged a lack of “international sensitivity” when he openly suggested US troops based in Okinawa patronize legal prostitution in Japan to reduce sex crimes.

“If there is one big mistake I made, that might have been my lack of understanding of culture behind the US sex industry – if you mention adult entertainment in the US, everyone thinks of prostitution,” Hashimoto said on television.

“I admit that my international sensitivity was quite poor when I had to operate beyond national borders”.

US officials rejected the proposal and the US State Deparment called Hashimoto’s comments “outrageous and offensive”.

Washington also slammed Hashimoto’s remarks that “comfort women” were “necessary” to keep Japanese soldiers in check.

US State Department spokeswoman Jen Psaki said the trafficking of women for sexual purposes during that era “was a grave human rights violation of enormous proportions”.

“We hope Japan will continue to work with its neighbors to address this,” Psaki told reporters.