NEW YORK: Violence that engulfed the Sudanese city of El-Fasher last October was a “preventable human rights catastrophe” in which thousands were killed and tens of thousands forced to flee after months of siege by the Rapid Support Forces, the UN high commissioner for human rights said on Monday. “After imposing 18 months of siege, starvation and bombardment, the Rapid Support Forces unleashed a wave of intense violence, in which thousands of people were killed in a matter of days, and tens of thousands fled in terror,” Volker Turk told the UN Human Rights Council in Geneva.