Thousands of Sudanese have migrated to neighboring Chad to escape fighting in the western region of Darfur, while thousands more have left the capital city of Khartoum due to the outbreak of intense gunfire Thursday after the failure of yet another cease-fire.
Forces commanded by two previously allied leaders of Sudan's ruling council began a violent power struggle last weekend that has so far killed over 330 people, tipping a nation reliant on food aid to what the United Nations calls a humanitarian catastrophe.
The fiercest battles between the army and the paramilitary Rapid Support Forces (RSF) have been around Khartoum, one of Africa's largest urban areas, and in Darfur, still scarred by a brutal conflict that ended three years ago.
Around 10,000 to 20,000 people fleeing the fighting have taken refuge in villages along the border inside Chad, U.N. refugee agency UNHCR and the World Food Programme (WFP) said on Thursday.
Eyewitnesses in the city of El-Obeid, east of Darfur, described clashes between the army and paramilitary forces and widespread looting.
In the capital and sister cities Omdurman and Bahri, residents gathered at bus terminals with suitcases after more explosions and gunfire in the morning.
"There's no food, supermarkets are empty, the situation isn't safe, honestly, so people are leaving," said a Khartoum resident who gave only his first name, Abdelmalek.
Many other locals remain trapped, along with thousands of foreigners, in a city rapidly degenerating into a war zone.
Burnt-out vehicles litter the streets, and shells have torn gaping holes in buildings, including now-closed hospitals, where bodies lie unburied.
Even before the conflict, around a quarter of Sudan's population was facing acute hunger. Still, the WFP halted one of its largest global operations in the country on Saturday after three workers were killed.
Sudan borders seven countries and sits strategically between Egypt, Saudi Arabia, Ethiopia and Africa's volatile Sahel region, so the hostilities risk fanning regional tensions.
Chad said it had stopped and disarmed a Sudanese contingent of 320 soldiers on Monday, while the RSF returned the Egyptian troops it had captured at the northern Merowe base at the weekend.
In an all-out push for a ceasefire, U.N. Secretary-General Antonio Guterres was holding a virtual summit with the African Union, Arab League and EU, among others, a diplomatic source said.
RSF leader General Mohamed Hamdan Dagalo told broadcaster Al Jazeera he was ready to implement a three-day truce over Eid, which marks the end of the Muslim holy month of Ramadan and will start on Friday or Saturday.
Dagalo, widely known as Hemedti, has said he supports short ceasefires several times, but each has quickly collapsed. However, military ruler General Abdel Fattah al-Burhan told Al Jazeera: "There is no other option but the military solution."
"We are talking about a humanitarian truce, we are talking about safe passages... we are not talking about sitting down with a criminal," Hemedti said, referring to Burhan.
In Geneva, the World Health Organisation urged the combatants to open a safe corridor for medics and to allow those trapped to flee. International powers, struggling to evacuate citizens after the airport and embassy districts were caught up in the violence, have also been pushing for truces,
The RSF has up to 100,000 troops, according to analysts. The army has artillery and fighter planes and controls access to Khartoum. It appeared to be trying to cut supply routes to RSF fighters, residents and witnesses said.
The United States said it was "not currently safe" to evacuate private citizens while Japan's defense ministry placed military transport aircraft in Djibouti to prepare for pulling 63 of its nationals out.
Since hostilities erupted, much of the fighting has focused on the compound housing the army HQ and Burhan's residence.
Burhan accused RSF's Dagalo, until last week his deputy on the council that has ruled since a coup two years ago, of "a power grab."
An alliance between the two men had mostly held since the ouster four years ago of long-time leader Omar al-Bashir, whose rule saw Sudan become an international pariah that was on the U.S. terrorism list.
In an interview with the Financial Times, Burhan said much of the RSF was now "out of control," accusing fighters of looting and attacking foreign diplomats and aid workers.
Washington has said it had preliminary indications the RSF was behind an attack on its diplomats, and witnesses say RSF gunmen have been involved in looting and attacks on aid workers.
Separately, Dagalo told the FT the armed forces were to blame for hitting hospitals and non-military targets, as well as the attacks on "diplomats and guests."
The latest violence was triggered by disagreement over an internationally backed plan to form a new civilian government. Both sides accuse the other of thwarting the transition.