Witnesses reported mass looting as gunmen fired rockets in bitter urban battles in the western Darfur region.
There have been multiple truce efforts since fighting broke out on April 15 .
On Thursday, the two sides agreed to extend a repeatedly broken ceasefire for three more days.
Khartoum
Fighting raged in Sudan on Friday, despite rival forces agreeing to extend a truce aimed to stem nearly two weeks of warfare that has killed hundreds and caused widespread destruction.
In the capital Khartoum, where foreign nations are scrambling to organise mass evacuations of their citizens, Turkey's defence ministry said a military transport aircraft came under fire.
Witnesses reported mass looting as gunmen fired rockets in bitter urban battles in the western Darfur region.
There have been multiple truce efforts since fighting broke out on April 15 between Sudan's army led by General Abdel Fattah al-Burhan and the paramilitary Rapid Support Forces (RSF) commanded by his former deputy and fellow coup leader Mohamed Hamdan Daglo. All have failed.
Broken ceasefire
On Thursday, the two sides agreed to extend a repeatedly broken ceasefire for three more days.
The United States, Saudi Arabia as well as the African Union, the United Nations and others welcomed the rival generals' "readiness to engage in dialogue" in a bid to create a "more durable cessation of hostilities and ensuring unimpeded humanitarian access".
Since a power struggle between Burhan and Daglo erupted into violence, fighter jets have pounded RSF positions with air strikes in densely packed districts of Khartoum, as fighters on the ground exchanged volleys of artillery and heavy machine gun fire.
In some parts of the city of some five million people, trenches have been dug as gunmen battle each other street by street.
Death toll
At least 512 people have been killed and 4,193 wounded in the fighting, according to health ministry figures, although the real death toll is likely much higher.
Fighting has also spread across Sudan, especially in Darfur, where witnesses reported intense conflict.
The Darfur Bar Association, a civil society group, said fighters were "launching rockets at houses" in El Geneina, state capital of West Darfur, as well reporting firing from "rifles, machine guns and anti-aircraft weapons".
Fighting has spread "nearly all over the city" and fighters have "looted camps for the displaced and the university hospital" as well as setting fire to "markets, public buildings, aid warehouses and banks", the Bar Association added.
It urged Burhan and Daglo to "immediately stop this foolish war that is being waged on the backs of civilians across Sudan".
‘Distribution of weapons’
The doctors' union said "dozens" have been killed or wounded in El Geneina, where the UN has said it has reports of the "distribution of weapons among local communities".
In El Fasher, state capital of North Darfur, medics are struggling to cope with the influx of wounded people.
"The situation is very, very difficult here," said Mohamed Gibreel, project coordinator for Doctors Without Borders (MSF) in El Fasher, adding that the hospital there had received 410 wounded patients.
"There is no water, there is also no electricity," Gibreel said in a video posted by MSF on Friday, which showed patients on the corridor of the crowded hospital. "It has impacted all life-saving services."
Aid to stave off famine
The World Food Programme has said the violence could plunge millions more into hunger in a country where 15 million people — one-third of the population — need aid to stave off famine.
At least five aid workers have been killed and swathes of aid operations suspended -- putting the lives of 50,000 acutely malnourished children "at real risk", the UN has warned.
Darfur is still reeling from the devastating war that raged in the 2000s when then hard-line president Omar al-Bashir crushed ethnic-minority rebels by creating the Janjaweed militia to carry out atrocities, a force that later formed the basis of Daglo's RSF.
War crimes
That conflict left at least 300,000 people killed and close to 2.5 million displaced, according to UN figures, and saw Bashir charged with war crimes, crimes against humanity and genocide by the International Criminal Court.
Burhan and Daglo — commonly known as Hemeti — seized power in a 2021 coup that derailed Sudan's transition to democracy, established after Bashir was ousted following mass protests in 2019.
But the two generals later fell out, most recently over the planned integration of the RSF into the regular army.
Residents of Khartoum have meanwhile been shuttered at home, running dangerously low on food, cash and fuel needed to get out, with only intermittent power and internet.
Tens of thousands have already fled to neighbouring countries including Chad, Egypt, Ethiopia and South Sudan.
The UN warns the fighting could result in up to 270,000 people fleeing.