OSAKA - Toru Hashimoto, co-leader of the opposition Japan Restoration Party and the mayor of Osaka, rebutted US criticism about his remarks that  the "comfort women" system run by the Japanese military during World War II was a necessity, local media reported on Friday.

The reports cited some Twitter comments written by the mayor saying that what the Japanese military did for the women was evil and "unforgivable," but that a look back at the history of the US occupation of Japan shows that American troops used Japanese women for the same purpose as well.

Hashimoto said the "hysterical focus" on the issue of the " comfort women" system under the Japanese military regime is quite unfair, and argued that in this respect it does not make sense for the US government as well as the international community to single out Japan for condemnation.

Earlier this week, the mayor told local reporters that apart from the issue of whether the women were coerced or not, he believes the "comfort women" system was "necessary to maintain discipline" in the Japanese military during the wartime.

US State Department spokeswoman Jen Psaki said on Thursday that the mayor's comments were "outrageous and offensive."

"As the United States has stated previously what happened in that era to these women who were trafficked for sexual purpose is deplorable and clearly a grave human rights violation of enormous proportions," she added.

Earlier in the week, Hashimoto proposed that US troops based in southern Japan should patronize legal adult entertainment establishment to reduce sex crime there.  Okinawa, but later he admitted that his remarks were inappropriate and showed a lack of international sensitivity, the local media reported.

But he said had no intention of retracting any of his earlier comments, though his remarks might have seemed inappropriate to people outside Japan with different values.

In a tweet Wednesday, Rep. Milke HYonda, a Democrat who has urged Japan to take responsibility for wartime sex slavery, called Hashimoto's remarks "contemptible and respulsive," and demanded Japan's government "apologize for this atrocity."

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.

Hashimoto's comments came amid continuing criticism of Prime Minister Shinzo Abe's earlier pledges to revise Japan's past apologies for wartime atrocities. Before he took office in December, Abe had advocated revising a 1993 statement by then- Prime Minister Yohei Kono acknowledging and expressing remorse for the suffering caused to the sex slaves.