Osaka's abrasive mayor on Friday hit back at US criticism of his remarks on wartime sex slavery, claiming US troops abused Japanese women during their seven-year occupation.
Washington denounced as "outrageous" comments by Toru Hashimoto, who said "comfort women" forced to provide sex to Japanese troops during World War II were a military necessity.
"Mayor Hashimoto's comments were outrageous and offensive," State Department spokeswoman Jen Psaki told reporters Thursday, urging Tokyo to work with its neighbors to address the past issue.
Up to 200,000 "comfort women" from Korea, China, the Philippines and elsewhere were forcibly drafted into brothels catering to the Japanese military during World War II, according to many mainstream historians.
But Hashimoto hit back on Twitter.
"Let me go straight to the point. When the US occupied Japan, didn't they make use of Japanese women?" Hashimoto tweeted to his million followers.
"I cannot help but point out that it is unfair for the US to criticize only Japan by putting aside acts by its own country," said Hashimoto, who has been mentioned as a possible future prime minister.