A United Nations human rights panel called on Japan on Thursday to undertake independent investigations of wartime sex slavery and apologize to the women who were victims before it was too late.

Some historians estimate that as many as 200,000 so-called comfort women, many from China and South Korea, were forced into the Imperial Japanese Army's brothels before and during World War II.

Last month, South Korea accused Japan of trying to undermine a landmark 1993 apology to the women when a Japanese panel reviewing the apology found that South Korea worked with Japan on its wording. China accused Japan of refusing to face up to its history, and even trying to "whitewash" it.

The UN Human Rights Committee, which was looking at the issue as part of a regularly scheduled review, said that all reparation claims brought by victims before Japanese courts have been dismissed, and all complaints seeking criminal investigations and prosecutions have been rejected on grounds of the statute of limitations.

"We want Japan to make the kind of statement that the families, the women themselves, the few who are still surviving, can recognize as an unambiguous, uninhibited acceptance of total responsibility for compelling them to engage for a part of their lives in something that could have only destroyed their lives," said Nigel Rodley, the British expert chairing the panel.

The panel urged Japan to "ensure that all allegations of sexual slavery or other human rights violations perpetrated by Japanese military during wartime against the 'comfort women', are effectively, independently and impartially investigated and that perpetrators are prosecuted and if found guilty, punished."

Such acts carried out against the will of the victims meant Japan had a "direct legal responsibility," it said.

Secret government records should be opened to investigators, who could include non-Japanese to strengthen the independence of the investigation, according to Rodley and Dutch committee member Cornelius Flinterman.

The panel also said Japan's position on the issue was "contradictory," in that it says the comfort women were generally recruited and transported through coercion, but they were not "forcibly deported."

"But given that the 1993 Kono declaration admitted that it was forcible, we have no doubts about it," Rodley said, referring to the government statement on comfort women.

"And what is troubling is that the delegation now seems to need to spea k out of both sides of its mouth," he said.

Japan has said compensation for women forced to work in the brothels was settled by a 1965 treaty establishing diplomatic ties with South Korea. Japan also set up a fund to make payments to the women from private contributions in 1995, but South Korea has said that was not official and so not good enough.