Sudan's paramilitary Rapid Support Forces (RSF) said it had agreed to a 72-hour truce on humanitarian grounds from 6 a.m. (0400 GMT) on Friday, to coincide with the Muslim holiday of Eid al-Fitr.
The capital, Khartoum, was rocked by bombing and shelling earlier on Friday. There was no immediate comment from the army and its chief, General Abdel Fattah al-Burhan, did not mention a ceasefire in a pre-recorded speech posted on the army's Facebook page.
"The truce coincides with the blessed Eid al-Fitr ... to open humanitarian corridors to evacuate citizens and give them the opportunity to greet their families," the RSF said in a statement.
Fighting between the RSF and Sudan's army erupted on Saturday, derailing an internationally backed plan for a transition to a civilian democracy four years after the fall of Islamist autocrat Omar al-Bashir to mass protests and two years after a military coup.
The RSF said it had to act in "self-defense" to repel what it described as a coup attempt, adding that it is committed to a "complete ceasefire" during the armistice period.
At least 350 people have been killed in the power struggle between two previously allied leaders of the ruling military junta, army chief Burhan and RSF leader General Mohamed Hamdan Dagalo.
The conflict has dashed hopes for progress towards democracy in Sudan, risks drawing in its neighbours and could play into regional competition between Russia and the United States.
The RSF had earlier condemned the military for what it said was new assaults.
"At this moment, when citizens are preparing to receive the first day of Eid al-Fitr, the neighbourhoods of Khartoum are waking up to the bombings of aircrafts and heavy artillery in a sweeping attack that is directly targeting residential neighbourhoods," the RSF said early on Friday.
U.N. Secretary-General Antonio Guterres on Thursday appealed for a ceasefire to allow civilians to reach safety.
Thousands of civilians streamed out of Khartoum as gunfire and explosions sounded on Thursday. Large numbers also crossed into Chad to flee fighting in the western region of Darfur.
A doctors' group said at least 26 people were killed and 33 were injured in El-Obeid, a city west of Khartoum, on Thursday. Witnesses there described clashes between the army and RSF troops and widespread looting.
'MILITARY SOLUTION'
Guterres, speaking to reporters after meeting virtually with the heads of the African Union, the Arab League and other organizations on Thursday, said: "There was a strong consensus on condemning ongoing fighting in Sudan and calling for cessation of hostilities as an immediate priority".
Urging a three-day ceasefire, he said civilians trapped in conflict zones should be allowed to escape and to seek medical treatment, food and other supplies. The United States endorsed the ceasefire proposal.
Burhan told Al Jazeera he would support a truce on condition it allowed citizens to move freely - something he said the RSF had prevented. He also said he saw no partner for negotiations, and "no other option but the military solution".
His rival, Dagalo, widely known as Hemedti, told Al Jazeera he was ready to implement a three-day truce. Dagalo has said several times he supports short ceasefires but each has quickly collapsed.
"We are talking about a humanitarian truce, we are talking about safe passages ... we are not talking about sitting down with a criminal," Dagalo said, referring to Burhan.
Burhan accused 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 overthrow of strongman Bashir, whose rule saw Sudan become an international pariah that was on the U.S. terrorism list.
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.
FIGHTING AND FLEEING
Much of the fighting has focused on the Khartoum compound housing the army headquarters and Burhan's residence. The embassy district and airport have also been the scene of clashes.
In Khartoum and sister cities Omdurman and Bahri, residents gathered on Thursday at bus terminals with suitcases.
"There's no food. Supermarkets are empty. The situation isn't safe," said a resident who gave only his first name, Abdelmalek.
Many people remain trapped, along with thousands of foreigners in a city that has become a war zone.
Burnt-out vehicles littered the streets and buildings had gaping holes from shells. Hospitals, where bodies lie unburied, were closed.
About 10,000 to 20,000 people have taken refuge in villages along the border inside Chad, U.N. refugee agency UNHCR and the World Food Programme (WFP) said.
Even before the conflict, about a quarter of Sudan's people were facing acute hunger, but the WFP halted one of its largest global operations in the country on Saturday after three of its 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.
