Fighting between two rival generals has spread to two cities in war-ravaged Sudan, witnesses said Friday, raising concerns for hundreds of thousands who have fled violence in the Darfur region.

The vast western region as well as the capital Khartoum have seen some of the worst bloodshed since fighting erupted on April 15 between Sudan’s army and the paramilitary Rapid Support Forces (RSF).

Battles resumed late Thursday in the North Darfur state capital of El Fasher, witnesses said, disrupting nearly two months of calm in the city that has become a shelter from the shelling, looting, rapes and summary executions reported in other parts of Darfur.

“This is the biggest gathering of civilians displaced in Darfur, with 600,000 people in El Fasher,” said Nathaniel Raymond of the Humanitarian Research Lab at the Yale School of Public Health.

One resident told AFP: “As night fell, we heard battles with heavy weapons from the city’s east.”

Witnesses also reported fighting in Al-Fulah, capital of West Kordofan state which border North Darfur.

Numerous rights groups and witnesses who fled Darfur have reported the massacre of civilians and ethnically driv-en attacks and killings, largely by paramilitary forces and their allied Arab tribal militias.

Many have fled across the western border to neighbouring Chad, while others have sought refuge in other parts of Darfur, where the International Criminal Court is looking into allegations of war crimes.

The region has long been the site of deadly fighting since a war that erupted in 2003 and saw the feared Janjaweed -- precursors of the RSF -- unleashed on ethnic minority rebels.

Further east, a resident of Al-Fulah said “the RSF are confronting the army and the police, and public buildings have been set on fire during their fire exchanges”.

“Shops were looted and there are dead on both sides, but no one can get to the bodies in this chaos,” said another witness in Al-Fulah.

The conflict has displaced some four million Sudanese, according to UN figures, and killed at least 3,900 people nationwide, according to a conservative estimate by the Armed Conflict Location & Event Data Project.