Renewed artillery exchanges rocked greater Khartoum early Wednesday as Sudan's warring generals resumed fighting just minutes after the latest US and Saudi-brokered ceasefire expired.
Already on Tuesday evening, an immense fire had engulfed the intelligence service's headquarters in the capital Khartoum with each side accusing the other of attacking it in violation of the 72-hour truce.
A source within the regular army, led by Abdel Fattah al-Burhan, accused rival paramilitaries loyal to his former deputy Mohamed Hamdan Daglo of shelling the building.
A source within the paramilitary Rapid Support Forces said an "army drone bombed the building where RSF fighters had gathered, sparking a fire and the partial destruction of the intelligence headquarters".
On Wednesday morning, residents of Omdurman, just across the Nile from Khartoum, reported heavy artillery exchanges within minutes of the ceasefire expiring at 6:00 am (0400 GMT).
Army warplanes flew low over several adjacent districts, the residents said.
The ceasefire, which coincided with an international donors' conference in Geneva on Monday, brought a brief respite to the millions of civilians who have been trapped by the fighting in greater Khartoum but an exodus of refugees continued to pour of the war's other main battleground Darfur.
Nationwide, more than 2,000 people have been killed since the power struggle between Burhan and Daglo erupted into fighting on April 15, the Armed Conflict Location and Event Data Project said.
More than 2.5 million people have fled their homes, of whom around 550,000 have sought refuge in neighbouring countries, fled abroad, according to the International Organization for Migration.
According to the US State Department, up to 1,100 people have been killed in the West Darfur state capital El Geneina alone.
Bodies have remained on the streets of the city, where months of unrest have left shops either vacant or gutted by looters.
One lay covered on the asphalt, in front of an armoured vehicle. A dead man was partially curled up outside a house. Several others appeared to be lying face down together on a dirt road.
Residents have fled en masse, grabbing whatever they could to escape to the border with Chad. At least 150,000 people have fled Darfur into Chad since the start of fighting, according to the UN.
The United Nations has spoken of possible "crimes against humanity" in Darfur as the conflict has "taken an ethnic dimension" in a region still reeling from a 2003 rebellion among non-Arab minorities that prompted then-strongman Omar al-Bashir to recruit the Arab Janjaweed militia, whose actions led to charges of genocide, war crimes and crimes against humanity.
Washington has said the RSF, which traces its origins to the Janjaweed, is "primarily" responsible for recent "atrocities" in Darfur, which is home to a quarter of Sudan's population.
In an audio recording Tuesday, Daglo denounced what he called "a tribal conflict" in El Geneina, claiming to have ordered his men "not to intervene" and accusing the army of "creating sedition by distributing weapons" to civilians.
Monday's donors' conference raised close to $1.5 billion in aid pledges for Sudan and neighbouring countries, but organisers said that amounted to only half of the estimated needs.
A record 25 million people -- more than half Sudan's population -- are in need of aid and protection, the United Nations says.
UN chief Antonio Guterres warned "the scale and speed of Sudan's descent into death and destruction is unprecedented."
"Without strong international support, Sudan could quickly become a locus of lawlessness, radiating insecurity across the region," he said.
In an interview with AFP Tuesday, UN High Commissioner for Refugees Filippo Grandi urged neighbouring countries to keep their borders open to Sudanese refugees despite concerns the violence and lawlessness could spill over.
"My appeal to all the neighbouring countries is to say I understand your security concerns, but please keep your borders open because these people are really fleeing for their lives," he said.
