The United States condemned as "outrageous and offensive" comments by Osaka Mayor Toru Hashimoto who said that Japan's military brothels were "necessary" during wartime.

State Department spokeswoman Jennifer Psaki told a press briefing Thursday that "what happened in that era to these women who were trafficked for sexual purposes is deplorable and clearly a grave human rights violation of enormous proportions."

The mayor, who's also co-leader of the conservative Japan Restoration Party, wrote on Twitter Friday that the U.S., UK, France and Germany also sexually employed local women during wartime and it's unfair to only condemn Japan.