Thousands of residents fled from Sudan's capital where witnesses reported bodies in the streets and embassies said more than 270 civilians had been killed in battles between the army and paramilitaries by Thursday, with no end in sight.

"Life in Khartoum is impossible if this war does not stop," said Alawya al-Tayeb, 33, on her way out of the city.

"I tried to make children not see the slain bodies on the streets," she said, adding that her youngsters are already suffering from trauma and will need treatment.

The Rapid Support Forces paramilitaries said they would "fully commit to a complete ceasefire" from 1600 GMT for 24 hours, as did the army.

But gunfire continued in Khartoum from the appointed time and into Wednesday night, according to witnesses.

It was the second day in a row a proposed humanitarian ceasefire failed to take hold.

The Sudanese army said that 177 Egyptian soldiers who had been captured by the RSF in the northern city of Merowe were evacuated Wednesday back to Egypt -- a close ally of the military establishment -- on four Egyptian military transport planes.

Other evacuation plans have been difficult to orchestrate, as foreign diplomats have been attacked and UN received reports of sexual violence against aid workers.

UN Secretary-General Antonio Guterres announced he would meet Thursday with the heads of the African Union, the Arab League and regional bloc the Intergovernmental Authority on Development, his spokesman told reporters.

The violence erupted on Saturday between forces of the two generals who seized power in a 2021 coup: army chief Abdel Fattah al-Burhan and his deputy Mohamed Hamdan Daglo who commands the RSF.

It followed a bitter dispute between them over the planned integration of the RSF into the regular army -- a key condition for a final deal aimed at restoring Sudan's democratic transition.

Heavy gunfire resounded and deafening explosions rattled buildings in Khartoum -- a city of five million people -- as thick black smoke rose from buildings around the army headquarters.

RSF fighters atop armoured vehicles and pickup trucks laden with weapons swarmed the streets. Fighter jets roared overhead and fired on RSF targets, the witnesses said.

Battles have damaged residential and commercial buildings, and civilians sheltering in their homes are becoming increasingly desperate, with dwindling food supplies, power outages, and a lack of running water.

- 'Even worse' -

"Neither side seems to be winning at the moment, and given the intensity of the violence, things could get even worse before the two generals come to the negotiating table," according to Clement Deshayes, a Sudan specialist at Paris's Sorbonne University.

Thousands aren't waiting and, according to witnesses, began leaving Khartoum by car or on foot.

They said the air was filled with the stench of dead bodies littering the streets.

Mohamed Saleh, 43, a government employee, said he was leaving behind "the terror of explosions" to stay with relatives in Madani, southeast of the capital.

"We were very worried fighters would start storming homes," he said.

Both forces must "refrain from unlawfully evicting people from their homes", during fighting that is "recklessly endangering the Sudanese people, diplomats and humanitarian aid workers", the US embassy wrote in a statement signed by 14 other diplomatic missions in Sudan.

The army said the central bank of the impoverished country had been looted and "huge sums of money" stolen by the RSF, which blamed army soldiers for "attacking homes of families".

- Hospitals shelled -

"The toll has been high, with initial estimated civilian deaths of more than 270," according to the embassies.

The real figure is thought to be much more, with many wounded unable to reach hospitals which are themselves being shelled, according to the official doctors' union.

About two-thirds of Khartoum's 59 main hospitals are "out of service", said the union which reported "severe shortages" in remaining facilities.

Japan said its defence ministry had begun the "necessary preparations" to evacuate around 60 of its nationals, including embassy staff.

Berlin aborted on Wednesday an evacuation attempt involving three military transport planes, which would have carried 150 citizens, according to German weekly Der Spiegel.

The US embassy in Khartoum said it started gathering citizens' personal details but tweeted: "Due to the uncertain security situation in Khartoum and closure of the airport, there are no plans for (a) US government-coordinated evacuation."

The defence minister in Chad, which borders Sudan's Darfur region, said around 320 Sudanese soldiers had fled over the border in fear of the RSF, which was created in 2013 by longtime autocrat Omar al-Bashir.

- Crackdown –

Military commanders toppled Bashir together in April 2019 following mass protests against his three decades of iron-fisted rule.

In October 2021 Burhan and Daglo worked together in the coup against the civilian government installed following Bashir's ouster, derailing an internationally backed transition.

Burhan, whose career advanced under Bashir, has maintained his coup was "necessary" to bring more factions into politics.

But Daglo, who rose to prominence during the Bashir government's scorched-earth policy against Darfuri rebels, has since called the coup a "mistake" that failed to bring about change and invigorated Bashir's remnants. - AFP