A survey by Japan's welfare ministry shows that children living apart from their guardians at welfare facilities have experienced sexual and physical abuse from other children.
As of March last year, more than 26,000 children nationwide were living in care facilities. They were unable to live with their parents due to abuse and other factors.
NHK asked all of the country's 47 prefectures about their children's protective institutions. It learned that at least 9 prefectures, including Tokyo, Saitama and Mie, had a total of 409 cases of child-against-child sexual abuse at such facilities during the five-year period that ended in March of this year.
A closer look at cases in which specific information was disclosed found that the victims were aged between 3 and 15, while their abusers were between 11 and 17.
Some cases of same-sex abuse were also reported.
The ministry is to carry out an investigation of welfare facilities nationwide during the current fiscal year, from April to March of next year, to confirm the facts.
It plans to include cases of psychological abuse, such as violent language and neglect, in its inquiry.
The ministry officials expressed their readiness to completely expose such practices, saying these facilities must be places where children's safety is guaranteed.
Rikkyo University Professor Emeritus Haruo Asai says some 60 percent of the children in such facilities have been abused at home. He says they may be adopting the practice as a means of gaining an upper hand on others.
He also pointed out the need to provide the victims with counseling.