The violence erupted Saturday after weeks of power struggles between the two generals who seized power in a 2021 coup, Sudan's Army chief Abdel Fattah al-Burhan and his deputy, Mohamed Hamdan Daglo, who commands the powerful paramilitary Rapid Support Forces (RSF), AFP reported.
The conflict, which has seen airstrikes, tanks on the streets, artillery fire and heavy gunfire in crowded neighbourhoods both in Khartoum and other cities across Sudan, has triggered international demands for an immediate ceasefire.
Despite the wide calls for a ceasefire, the two generals have appeared in no mood for talks with each one calling the other "criminal".
As the fighting showed no sign of abating, Daglo took to Twitter to call for the international community to intervene against Burhan.
The UN chief in Sudan on Monday slammed the failure by both the army and rival paramilitary forces to stop fighting during an agreed humanitarian pause to evacuate the wounded.
The conflict has claimed the lives of at least 97 civilians and "dozens" of fighters from both sides, medics said, adding about 942 people have been injured.
But the number of casualties is thought to be far higher, with many wounded unable to reach hospitals due to difficulties in movement amid the fighting.
The doctors' union warned the fighting had "heavily damaged" multiple hospitals in Khartoum and other cities, with some rendered completely "out of service".
The World Health Organization had already warned that several of Khartoum's nine hospitals receiving injured civilians "have run out of blood, transfusion equipment, intravenous fluids and other vital supplies".
UN Special Representative Volker Perthes, who is in Khartoum, said he was "extremely disappointed" by the failure of both sides to abide by an agreed humanitarian pause on Sunday to evacuate the wounded.
The violence has forced terrified people to shelter in their homes with fears of a prolonged conflict that could plunge Sudan into deeper chaos, dashing hopes for return to civilian rule.
The RSF was created under former autocrat Omar al-Bashir in 2013, emerging from the Janjaweed militia that his government unleashed against non-Arab ethnic minorities in Darfur a decade earlier, drawing accusations of war crimes.
The fighting broke out after bitter disagreements between Burhan and Daglo over the planned integration of the RSF into the regular army – a key condition for a final deal aimed at ending a crisis since the 2021 military coup they orchestrated together.
The two sides accuse the other of starting the fighting, and both claim the upper hand by declaring control of key sites, including the airport and the presidential palace – none of which could be independently verified.
UN Secretary-General Antonio Guterres has warned an escalation in the fighting would "further aggravate the already precarious humanitarian situation".