The blackout makes it impossible to assess the full scale of the massacres, but the videos that have trickled out provide a horrifying glimpse. Some were filmed and proudly posted online by RSF fighters, showing them taunting crowds of terrified people before shooting them at close range. Most prominent in the videos is RSF Brigadier General Al-Fateh Abdullah Idris, nicknamed Abu Lulu, who boasted on Monday that he may have killed more than 2,000 people.

An aid worker helping fleeing civilians, speaking on the condition of anonymity for safety reasons, said his organization had heard multiple accounts that men and teenage boys were being separated from their families and beaten, tortured or killed. “Numerous reports emerged of hundreds, if not thousands, of civilians in El Fashir being targeted and killed on ethnic grounds,” the aid worker said. The U.N. Human Rights Office said Monday it was “receiving multiple, alarming reports” that RSF forces were “carrying out atrocities, including summary executions.”