At least 13 civilians were killed in an airstrike attributed to the Rapid Support Forces (RSF) that hit a mosque in the besieged city of El-Fasher in Sudan’s Darfur region, witnesses told Agence France-Presse on Thursday.

“Shells hit the Abu Shouk neighborhood mosque this afternoon. We pulled 13 bodies from under the rubble,” one witness said.

A survivor reported that around 70 families had been sheltering within the mosque’s compound after RSF fighters stormed their homes the previous day. “Artillery shells killed 13 people, wounded 20 others, and destroyed part of the mosque,” he said.

El-Fasher, the last major city in North Darfur under army control, has been under siege for more than a year amid the ongoing conflict between the Sudanese army and the RSF.