Sudan’s paramilitary Rapid Support Forces killed more than 1,000 civilians during three days of attacks on the Zamzam displacement camp in April, the U.N. said Thursday as it called for a war crimes investigation.

A report from the U.N. human rights office said it had documented widespread killings, sexual violence, torture and abductions committed during the brutal offensive by the RSF, which has been fighting Sudan's regular army since 2023.

The rights office "documented the killing of at least 1,013 civilians" in that attack between April 11 and 13, the report said, adding that it had also confirmed that "at least 319 individuals were summarily executed."

"Some were killed in their homes during house-to-house searches by the RSF; others were killed in the main market, in schools, health facilities and mosques," the office said in a statement.

More than 400,000 inhabitants of the camp for internally displaced people (IDPs) were displaced once again due to the attack, it added.