[Read more: Detentions of child migrants at the U.S. border have surged to record levels]

The federal government received more than 4,500 complaints in four years about the sexual abuse of immigrant children who were being held at government-funded detention facilities, including an increase in complaints while the Trump administration’s policy of separating migrant families at the border was in place, the Justice Department revealed this week.

The records, which involve children who had entered the country alone or had been separated from their parents, detailed allegations that adult staff members had harassed and assaulted children, including fondling and kissing minors, watching them as they showered, and raping them. They also included cases of suspected abuse of children by other minors.

From October 2014 to July 2018, the Office of Refugee Resettlement, a part of the Health and Human Services Department that cares for so-called unaccompanied minors, received a total of 4,556 allegations of sexual abuse or sexual harassment, 1,303 of which were referred to the Justice Department. Of those 1,303 cases deemed the most serious, 178 were accusations that adult staff members had sexually assaulted immigrant children, while the rest were allegations of minors assaulting other minors, the report said.

“The safety of minors is our top concern when administering the UAC program,” Jonathan H. Hayes, the acting director of the Office of Refugee Resettlement, said in a statement, using an abbreviation for unaccompanied children. “None of the allegations involved O.R.R. federal staff. These allegations were all fully investigated and remedial action was taken where appropriate.”