United Nations chief Antonio Guterres has strongly condemned the outbreak of violence in Sudan and called on the leaders of the warring sides to immediately cease hostilities and engage in dialogue, according to Aljazeera.
Guterres made the comments on Monday, the third day of fighting between the Sudanese army and the powerful Rapid Support Forces (RSF) paramilitary group. Guterres will discuss the situation on Thursday with the heads of the African Union, Arab League and other organisations.
Residents of Sudan's capital reported renewed heavy gunfire on Thursday as thousands tried to flee fighting that has killed scores of civilians before the Eid holiday marking the end of the holy month of Ramadan, Reuters reports.
Khartoum and its sister cities Omdurman and Bahri, one of Africa's most populous urban areas, have been rocked by battles this week. Locals and thousands of foreigners are stranded and food supplies have run short.
Gunfire was heard in Bahri and residents reported clashes west of Omdurman where they said the army had moved to block the arrival of RSF reinforcements, as both sides violated a 24-hour ceasefire they had said they would respect from Wednesday.
The RSF issued a statement saying it came under attack in Omdurman and inflicted losses on the army in response, including shooting down two helicopters. Reuters could not independently verify the RSF's claims.
The army has artillery and fighter planes, and controls access to Khartoum. It appeared to be trying to cut supply routes to RSF fighters, says residents and witnesses.
"There's no food, supermarkets are empty, the situation isn't safe, honestly, so people are leaving," said a Khartoum resident
Sudan sits strategically between Egypt, Saudi Arabia, Ethiopia and Africa's volatile Sahel region, and the power struggle there risks fanning regional tensions.
The RSF has returned Egyptian troops it had captured at the northern Merowe base at the weekend, and western neighbour Chad said it had stopped and disarmed a Sudanese contingent of 320 soldiers on Monday, among thousands of refugees crossing the border from Sudan's Darfur region.
Since hostilities erupted on Saturday, some of the most intense fighting has been around the compound housing the army HQ and the residence of Sudan's military ruler, General Abdel Fattah al-Burhan.
Burhan accused RSF leader General Mohamed Hamdan Dagalo, until last week his deputy on the military council that has ruled since a coup two years ago, of "a power grab". A fragile alliance between the two men had mostly held since the ouster four years ago of veteran autocrat Omar al-Bashir.
In an interview with the Financial Times, Burhan said much of the RSF was now "out of control", accusing its fighters of looting and attacking foreign diplomats and aid workers.
International powers, struggling to evacuate citizens after the airport and embassy districts were caught up in the violence, have been pushing for truces, to little effect.
The violence was triggered by disagreement over an internationally-backed plan to form a new civilian government and integrate the RSF into the regular military. Both sides accuse the other of thwarting the transition.