Gunmen from Sudan's paramilitary Rapid Support Forces were accused of attacking a remote town on Friday before going on a shooting and looting rampage that witnesses said "terrorized" its people.
For nearly three months, the RSF commanded by Mohamed Hamdan Daglo has fought the regular army under General Abdel Fattah al-Burhan in a war that has claimed the lives of at least 3,000 people and displaced millions.
The RSF was "looting banks and public buildings" in Bara, 50 kilometres (30 miles) northeast of El-Obeid, the capital of North Kordofan, a witness in the town said, AFP reported.
"We're being terrorized: they shoot and loot, and the army and police are nowhere to be seen," said another resident, Abdelmohsen Ibrahim.
"Even if the army tries to come from El-Obeid, the RSF are in control of the El-Obeid-Bara road."
El-Obeid, 350 kilometres south of Khartoum, is a strategic logistical and commercial hub, with an airport and huge warehouses for the storage of foodstuffs.
The fighting since April 15 has been centred on the capital Khartoum as well as North Kordofan and the vast western region of Darfur, where the United Nations has warned of possible "crimes against humanity".
Residents on Friday reported continued armed clashes in the capital's twin city of Omdurman across the Nile.
Witnesses also reported "air strikes in the area of the state broadcaster's headquarters in Omdurman and anti-aircraft fire to repel" the raids.
Another witness reported an air strike on an RSF base in northern Khartoum.
Many civilians have accused the RSF of carrying out acts of violence against them, while also charging that the armed forces have done little to protect them.
Since the war erupted, the RSF has established bases in residential areas while the army has struggled to take advantage of its air superiority.
The RSF has been accused of forcing civilians out of their homes, seizing their vehicles, robbing them and raping women as they flee to neighbouring countries.
The current conflict has seen myriad successive truces agreed and systematically violated, amid mediation from international and African actors.
The east African regional bloc IGAD on Friday announced that a meeting of heads of state tasked with resolving Sudan's crisis would be held in the Ethiopian capital Monday, the bloc's spokesman Nour Mahmoud Sheikh al-Jumaa said.
An IGAD official told AFP on condition of anonymity that both Burhan and Daglo had been invited to the summit.
"They may attend or send high-level representatives," the official said.
The bloc had previously announced the expansion of the mechanism to resolve Sudan's crisis to include Ethiopia, alongside Kenya, Somalia and South Sudan.
As part of that arrangement, Kenya was announced as the chair of the quartet, drawing objections from Sudan's foreign ministry which alleged that Nairobi had "adopted the positions of the RSF militia, sheltered its people and offered them various forms of support".
