Greek police say four Pakistani teenagers have been arrested in a refugee camp on the eastern Aegean island of Lesbos on charges of raping another teenage boy.

Police said Wednesday the four boys, all aged 17, were arrested in Moria camp Sunday and face felony charges of rape and child pornography.

The four are accused of collectively assaulting a 16-year-old, also from Pakistan, and recording their actions on mobile phones. The 16-year-old was seen by a medical examiner and a child psychologist, while the four arrested boys are to appear before an investigative judge.

More than 5,800 refugees and migrants are stuck on Lesbos, whose camps have a capacity of 3,500. Although fights between residents are frequent in camps on the islands, rapes are rare.