US Secretary of State Antony Blinken held separate calls with the army chief and head of the paramilitary Rapid Response Forces (RSF), whose power struggle has killed at least 185 people and derailed an internationally-backed deal for a shift to civilian government after decades of autocracy and military rule.

Gunfire echoed across Sudan’s capital for a fourth day on Tuesday, accompanied by the sound of warplanes and explosions, a Reuters reporter said. Residents in Khartoum’s twin city of Omdurman, on the other side of the Nile, also reported air strikes that shook buildings and anti-aircraft fire.

Blinken said a US diplomatic convoy came under fire on Monday in an apparent attack by fighters associated with the RSF, adding that all those in the convoy were safe. He called the incident “reckless” and said any attacks or threats to US diplomats were unacceptable.

Blinken, speaking in Japan, said he had telephoned both RSF leader General Mohamed Hamdan Dagalo, known as Hemedti, and Sudan’s army chief General Abdel Fattah Al-Burhan, appealing for a 24-hour cease-fire “to allow the Sudanese to be safely reunited with families” and to provide them with relief.

Fighting between Sudan’s army and the RSF that erupted on Saturday has killed at least 185 people and injured more than 1,800, UN envoy Volker Perthes said on Monday.

The RSF’s Hemedti, whose whereabouts have not been disclosed since fighting began, said he had “discussed pressing issues” with Blinken during their call and more talks were planned.

In posts on Twitter he said the RSF approved a 24-hour armistice. The RSF also issued a statement saying it was waging a continuing battle to restore “the rights of our people.”

Both sides have offered truces in previous days, but the fighting has not stopped.

The clashes in Khartoum and its adjoining sister cities of Omdurman and Bahri are the worst in decades and risk tearing Sudan between two military factions that had shared power during a rocky political transition.

Army chief Burhan has headed Sudan’s ruling council since Bashir’s ouster and shared power with civilians before leading a 2021 coup. RSF leader Hemedti is his deputy.

The battling factions both claim to have made gains amid airstrikes and fighting across the capital, Khartoum, and its neighboring cities of Omdurman and Bahri.

The violence has caused power and water cuts in some areas, and left many residents stranded in the final days of Ramadan when Muslims fast during daylight hours.

Health services have been widely disrupted and most major hospitals had gone out of service, according to a doctors’ group monitoring the conflict.

“Our nerves are frayed,” said one woman living in Omdurman, close to a state broadcasting building that has been fought over. “This is the hardest thing a person can go through.”

An already precarious humanitarian situation in Sudan has deteriorated, and UN officials say many aid programs have been suspended.

Fighting in Darfur has raised the specter of renewed conflict in a region that from 2003 was plagued by years of bloody warfare.

Perthes, the UN envoy to Sudan, said on Monday the two sides showed no signs of being willing to negotiate.

“The two sides who are fighting are not giving the impression that they want mediation for a peace between them right away,” Perthes told reporters by videolink from Khartoum.

The violence could destabilize a volatile region and play into competition for influence there between Russia and the United States, and among regional powers that have courted different actors in Sudan.

Egypt is the most important backer of Sudan’s armed forces while Hemedti has cultivated ties with foreign powers including the United Arab Emirates and Russia.

Egyptian President Abdel Fattah El-Sisi said late on Monday that he was in regular contact with the army and RSF to “encourage them to accept a cease-fire and spare the blood of the Sudanese people.” He said Egyptian troops who the RSF has been holding in Sudan were there to conduct exercises.

The army’s media office said Burhan would pardon RSF officers and soldiers who surrender and “lay down their arms.” Those that do would be absorbed into the armed forces, he said.

The eruption of fighting followed rising tensions over the RSF’s integration into the military under a civilian transition plan.

While the army is larger and has air power, the RSF is widely deployed in neighborhoods of Khartoum and other cities, giving neither faction the edge for a quick victory.

In a second security incident involving diplomats, the European Union’s ambassador to Sudan was assaulted in his residency on Monday, the EU’s foreign policy chief said, without giving details.

Since the fighting began, Burhan has branded the RSF a rebel group and ordered it to be dissolved. Hemedti has accused the army chief of visiting destruction on his country.