Air strikes and artillery rocked Khartoum on Saturday as Sudan entered a third week of fighting between rival military forces despite a ceasefire, prompting more civilians to flee and renewed warnings of wider instability if the war is not stopped.
A UN envoy said that the warring sides who have so far shown no sign of compromise were now more open to negotiations - though no date had been set.
Meanwhile, UN Secretary-General Antonio Guterres said that "there is no right to go on fighting for power when the country is falling apart”.
More than 500 people have been killed since battles erupted on April 15 between the forces of army chief Abdel Fattah al-Burhan and his number two Mohamed Hamdan Daglo, who commands the paramilitary Rapid Support Forces (RSF).
Despite shelling early in the morning, residents of Khartoum and its neighbouring cities said the fighting had been less intense on Saturday than in recent days.
The sides have continued to battle it out during a series of ceasefires mediated by foreign powers. The latest 72-hour truce expires at midnight on Sunday.
The RSF on Saturday accused the army of violating the ceasefire in areas under its control.
There was no immediate comment from the army, which has previously blamed the RSF for violations.
The prospects of negotiations between the leaders of the two sides have so far seemed bleak.
On Friday, Fattah said he would never sit down with the RSF's "rebel" leader, referring to Dagalo, commonly known as Hemedti.
The RSF chief in turn said he would talk only after the army ceased hostilities.
Nonetheless, the UN special representative in Sudan, Volker Perthes, said he had recently sensed a change in the sides' attitudes and they were more open to negotiations.
"The word 'negotiations' or 'talks' was not there in their discourse in the first week or so," Perthes said.
He said the sides had nominated representatives for talks which had been suggested for Jeddah, Saudi Arabia, or Juba in South Sudan, though he said there was a practical question over whether they could get there to "actually sit together".
The UN said more than 75,000 people had been internally displaced by the fighting.
Tens of thousands of people have fled to neighbouring countries, while foreign governments have organised a major evacuation of expatriates, including those from Bangladesh.
