Overnight, the heavy explosions that had previously rocked the city in recent days had subsided, but on Saturday morning, fighting resumed.
Heavy gunfire, loud explosions, and fighter jets roared in many parts of the capital Saturday morning, according to witnesses.
Violence broke out on April 15 between forces loyal to army chief Abdel Fattah al-Burhan and his deputy turned rival Mohamed Hamdan Daglo, who commands the powerful paramilitary Rapid Support Forces (RSF).
The former allies seized power in a 2021 coup but later fell out in a bitter power struggle.
The army announced Friday that it had "agreed to a ceasefire for three days" for the Eid al-Fitr holiday that marks the end of the Muslim holy month of Ramadan, which UN Secretary-General Antonio Guterres and US Secretary of State Antony Blinken had called for a day earlier.
Daglo said in a statement he had "discussed the current crisis" with Guterres, and was "focused on the humanitarian truce, safe passages, and protecting humanitarian workers".
Two previous 24-hour ceasefires announced earlier in the week were also ignored.
The fighting has seen the RSF -- a force tens of thousands strong, formed from members of the Janjaweed militia that led years of violence in the western Darfur region -- take on the regular army, with neither side seemingly having seized the advantage.