The “overwhelming majority” of women and older girls who passed through Libya as migrants reported being gang-raped by traffickers or witnessed others taken away to be abused, the United Nations said Thursday in a report based on hundreds of interviews.

The Office of the High Commissioner for Human Rights said its report, along with the U.N. support mission in Libya, turned up “unimaginable horrors” among migrants who seek to reach Europe the through largely lawless country.

The report covers January 2017 to August 2018.

A statement said investigators pulled together 1,300 first-hand accounts detailing “a terrible litany of violations and abuses committed by a range of state officials, armed groups, smugglers and traffickers against migrants and refugees.”

Those included unlawful killings, torture, arbitrary detention, gang rape, slavery, forced labor and extortion.

The report comes as European Union leaders pursue efforts to beef up the bloc’s external borders to stop large numbers of migrants from entering Europe. Many migrants who have been caught trying to cross the Mediterranean have been returned to Libya — and put in detention centers.

Story by The Associated Press