Heavy gunfire echoed in the background of live feeds by Arab television news channels and residents told Reuters that shooting had not ceased, with one saying they had heard an air strike being carried out in Omdurman, Khartoum's sister city on the opposite bank of the Nile river.
The ceasefire that formally took effect at 6 p.m. (1600 GMT) would not extend beyond the agreed 24 hours, Army General Shams El Din Kabbashi, a member of Sudan's ruling military council, said earlier on al Arabiya TV.
Fighting appeared to tail off close to the deadline for the ceasefire, which coincided with the evening breaking of the daily fast during the Islamic holy month of Ramadan, but heavy gunfire reverberated around the capital region after 6 p.m.
A Reuters reporter in Khartoum said he heard tanks firing after the ceasefire was due to have started. The source of shooting was unclear, though the RSF accused the military of violating the ceasefire within 15 minutes of it taking effect.
Early on Tuesday, gunfire echoed across Khartoum accompanied by the sound of warplanes and explosions. Residents in the neighboring cities of Omdurman and Bahri reported air strikes that shook buildings and anti-aircraft fire. Fighting also raged in the west of the country, the United Nations said.
The conflict between Sudan's armed ruling factions broke out four days ago and has killed at least 185 people across the country, triggering what the United Nations has described as a catastrophic humanitarian crisis, including the near collapse of the health system.
"Bombardments usually start around 4:00 am and they continue for a few hours, but today they haven't stopped," said Khartoum resident Dallia Mohamed Abdelmoniem.
"We haven't slept in the past four days," she said, adding her family had been staying indoors "trying to keep our sanity intact".
Families waited on Tuesday, heavy suitcases in hand, for the few buses heading south from the capital, according to AFP reporters, as more people use rare lulls in the fighting to escape Khartoum.
Secretary Blinken held separate calls with the rival commanders — both RSF leader Gen. Mohamed Hamdan Dagalo, known as Hemedti, and Gen. Abdel Fattah al-Burhan, appealing for the 24-hour cease-fire "to allow the Sudanese to be safely reunited with families" and to provide them with relief.
After the call, Hemedti said the RSF approved the cease-fire to ensure the safe passage of civilians and the evacuation of the wounded.
In a post on Twitter, Hemedti said he had "discussed pressing issues" with Blinken and more talks were planned. The RSF also issued a statement saying it was waging a battle to restore "the rights of our people" in what it called a new revolution.
Hemedti's whereabouts have not been disclosed since fighting began.
As for the attack on the U.S. diplomatic convoy, Blinken said the vehicles were marked with diplomatic license plates and bearing U.S. flags. Initial reports suggest the attack was undertaken by forces associated with the RSF, he said, calling the action "reckless." Blinken said all U.S. personnel were safe after the incident.
A previous shorter cease-fire agreed for Sunday was not fully observed. Artillery volleys, strikes by combat aircraft and street fighting have made it almost impossible to travel in Khartoum, trapping residents and foreigners in their homes.
The main international airport has been under attack, halting commercial flights.
Fighters have attacked aid workers, hospitals and diplomats, including an EU ambassador assaulted in his home. Three workers for the World Food Program were killed in the fighting on Saturday, and a U.N. plane was hit in crossfire.
The International Federation of Red Cross and Red Crescent Societies said it was nearly impossible to provide humanitarian services around the capital. It warned that Sudan's health system was at risk of breakdown.
The outbreak of fighting followed rising tensions over a plan for the RSF's integration into the regular military.
Discord over the timetable for that process delayed the signing of the framework deal to launch a civilian transition that was due to be signed earlier this month.
This report was sourced from Reuters and Agence France-Presse.
