The sources said the attack occurred in Nyala, the capital of Darfur South state, from which 50,000 people have been forced to flee since August 11, according to the United Nations.

The sprawling region of Darfur saw some of the worst bouts of violence in the conflict, and the fighting there has morphed into ethnic clashes with RSF and allied Arab militia targeting ethnic African communities.

Clashes also intensified earlier this month in the provinces of South Kordofan and West Kordofan.

The fighting is estimated to have killed at least 4,000 people, according to the U.N. human rights office, though activists and doctors on the ground say the death toll is likely far higher.

More than 4.6 million people have been displaced, according to the U.N. migration agency. Those include over 3.6 million who fled to safer areas inside Sudan and more than 1 million others who crossed into neighboring countries.

The conflict has turned Khartoum and other urban areas into battlefields. Many residents live without water and electricity, and the country’s health care system has nearly collapsed.