The confirmation yesterday, ahead of a conference on women later this month, is likely to renew anger among the dwindling number of surviving former "comfort women", who say the country has never taken full responsibility for what it did in wartime.
It could also further complicate a troubled deal between Tokyo and Seoul sealed in late December -- one their top diplomats called "final and irreversible" -- but which has sparked anger among former South Korean comfort women and their supporters.
Tokyo has offered repeated apologies over the issue, and says that while there was military involvement in the establishment of "comfort stations" there is no evidence its officials were involved in the abduction of women for the purpose.
It says private brokers were responsible in some cases, and in others, the women were common prostitutes.
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In a report submitted to the committee in December and posted on its website, Japan said it carried out a "full-scale fact-finding study" by investigating documents and interviewing people including former military officials since the early 1990s.
"The Japanese delegation will explain our position" on that and other women's issues at the Geneva conference that begins February 15, a foreign ministry official in charge of gender issues told AFP, declining to give her name.
The UN-sponsored conference is part of the ongoing Convention on the Elimination of All Forms of Discrimination against Women.