Khalid Abdelaziz,  Nafisa Eltahir Reuters

Violence flared in the western Sudanese city of Nyala and elsewhere in the state of South Darfur on Sunday, witnesses said, threatening to engulf the region in Sudan’s protracted war.

The conflict has brought daily battles to the streets of the capital of Khartoum, a revival of ethnically targeted attacks in West Darfur, and the displacement of more than 4 million people within Sudan and across its borders into Chad, Egypt, South Sudan and other countries.

Clashes between the Sudanese army and paramilitary Rapid Support Forces have flared periodically in Nyala, the country’s second biggest city and a strategic hub for the fragile Darfur region.

The latest flare-up has lasted three days, with both the army and RSF firing artillery into residential neighbourhoods, witnesses told Reuters. Fighting has damaged electricity, water, and telecoms networks.

At least eight people were killed on Saturday alone, according to the Darfur Bar Association, a national human rights monitor.

In recent days, fighting has extended 100 km (60 miles) to the west of Nyala, in the Kubum area, killing dozens, according to witnesses.

The bar association said Arab tribesmen equipped with RSF vehicles attacked the area, burning the market and raiding the police station in an attack on a rival Arab tribe. The fighting killed 24 people, it said.

Several Arab tribes have pledged their allegiance to the RSF.

“We call on all elements not to get dragged into the conflict whose aim is power in the centre of the country,” the bar association said.

On Friday, Meta removed official Facebook pages belonging to the RSF for violating its “dangerous organisations and individuals policy”.

Extensive fighting in the area risks returning Darfur to the bloody attacks of the early 2000s when “Janjaweed” militias – from which the RSF formed – helped the army crush a rebellion by mainly non-Arab groups.

Some 300,000 people were killed, the U.N. estimates, and Sudanese leaders are wanted by the International Criminal Court for genocide and crimes against humanity.

The UN’s special representative to Sudan, Volker Perthes, warned in July that the conflict showed no signs of a quick resolution and “risked morphing into an ethnicised civil war”.

Diplomatic mediation efforts has so far failed and ceasefires have been used by both sides to regroup.