A new report from the U.S. Justice Department shows youths are sexually abused more frequently in juvenile detention centers that are understaffed and have more gang violence and more offender complaints.

The agency's Bureau of Justice Statistics released the report Tuesday. It examined the effect of juvenile facilities on sex abuse rates.

The study found that lower rates of sexual victimization were reported in facilities with higher staffing levels, less violence and fewer overall complaints.

Lovisa Stannow is executive director of Just Detention International, a prisoner advocacy group that works to stop sex abuse behind bars. She said in a statement the findings were encouraging because they show that federal standards designed to stop sex assault work.

Stannow says she's frustrated by some correctional officials who maintain sexual violence is outside their control.