The UN’s top humanitarian official has called for an immediate ceasefire in El Fasher, the capital of Sudan’s North Darfur region, amid reports of significant civilian deaths, attacks on hospitals and the city’s reported capture by the Rapid Support Forces (RSF).

Aid workers worried Thursday that only a trickle of the people believed to have fled a paramilitary force that seized a city in Sudan’s Darfur region have reached safety, as hundreds reportedly have been killed in the attack and while making their escape.

People have been arriving to a town west of el-Fasher, having fled on foot during the attack by the Rapid Support Forces, which has been fighting troops allied to Sudan's military since 2023 in the East African nation.

Already, the World Health Organization has warned the violence reportedly killed 460 people in a hospital in el-Fasher. Witnesses have told The Associated Press that RSF fighters also went from house to house, beating and shooting people, including women and children. The RSF on Thursday for the first time directly denied carrying out killings at the hospital as international outrage grows.

Disrupted communications around el-Fasher has made assessing the devastation that much more difficult. Experts have said satellite photos also appear to show bodies in the streets of the city after the RSF attack.

The smaller number of people reaching the town of Tawila, about 60 kilometers (35 miles) west of el-Fasher and not under the paramilitary group's control, have aid workers fearing the worst.