Outspoken Osaka Mayor Toru Hashimoto, seeking to quell an international furore, denied on Monday that he had ever meant to excuse Japan's wartime military brothels and said Japan should apologise to the Asian and other women forced to work there.
Still, in comments likely to keep the controversy alive, Hashimoto said historical research was needed to determine whether Japan "as a state" was directly involved in human trafficking of the "comfort women", as those who worked in the brothels are euphemistically known in Japan.
He also urged other countries to face up to the possibility of similar offences regarding "sex and the battlefield".
Hashimoto, the populist co-leader of a small right-wing party, sparked a storm of criticism at home and abroad when he said earlier this month that the military brothels had been "necessary" at the time and that Japan had been unfairly singled out for practices common among other militaries during wartime.
Those remarks have further eroded dwindling voter support for his once-rising Japan Restoration Party, making it a less attractive potential ally for Prime Minister Shinzo Abe as he eyes sensitive revisions to the country's pacifist post-war constitution.
Hashimoto did not withdraw his remarks but said they had been reported only in part, and had been misunderstood.
"I am totally in agreement that the use of 'comfort women' by Japanese soldiers before and during the World War Two was an inexcusable act that violated the dignity and human rights of the women in which large numbers of Korean and Japanese were included," Hashimoto said at the start of a nearly three-hour news conference before foreign and domestic media.
"I also strongly believe that Japan must reflect upon its past offenses with humility and express a heartfelt apology and regret to those women who suffered from the wartime atrocities as comfort women," he said in an English version of the statement. "I have never condoned the use of comfort women."
Hashimoto's popularity has waned and the "comfort women" controversy has added to his woes. Only 3 percent of voters plan to cast their ballots for his party in a July upper house election, down six percentage points from an April questionnaire, a survey by the Nikkei business daily showed.
The issue of the "comfort women" - most of whom were Asian and many Korean - has long been a point of contention between Tokyo and Seoul. Japan says the matter of compensation for the women was settled under a 1965 treaty establishing diplomatic ties with South Korea.
In 1995 Japan set up at fund to make payments to the women from private donations, but Seoul says that was unofficial and therefore insufficient.
Hashimoto said that given the dispute over compensation, Seoul should take the issue to the International Court of Justice, a suggestion which brought a sharp rebuke from South Korea.
"I think Japan's recent ... remarks are throwing cold water onto our government's will to strengthen friendship between Korea and Japan more than ever," Foreign Minister Yun Byung-se told reporters.
"If such circumstances do not improve, not only summit-level but other high-ranking exchanges won't be that easy," Yun added.
Japanese Prime Minister Abe caused controversy during his first term in 2006-2007 by saying there was no proof that Japan's military had kidnapped women to work in the brothels.
He has, however, sought to distance himself from Hashimoto's remarks and his government has drawn back from early signals that it might revise a landmark 1993 statement by then-Chief Cabinet Minister Yohei Kono that acknowledged military involvement in coercing the women, and apologised to them.
Hashimoto said there was no doubt that women had been coerced into working in the brothels, and that Japan's military supervised the facilities and in some cases provided military vehicles and ships to transport the women.
But he said the Kono Statement was ambiguous on whether Japan "as a state" had been involved in human trafficking, and called for joint research by Japanese and South Korean scholars into that point.
Hashimoto also apologised for and retracted his remark that U.S. soldiers currently stationed on Japan's Okinawa island should use the local sex industry more to "control their sexual energies". Okinawa is host to the bulk of U.S. forces in Japan, and many residents object to their presence, which they associate with sexual and other crimes as well as pollution and accidents.
A Pentagon spokesman told the Asahi newspaper that Hashimoto's original remarks went against the policies and values of the U.S. forces.
Hashimoto said his comment reflected his wish that the United States take needed measures to alleviate the suffering caused in Okinawa by crimes committed by the U.S. military.