UN secretary-general Antonio Guterres has said Sudan is on the brink of a “full-scale civil war” as fierce clashes between rival generals continued in the capital Khartoum.

He warned that the war between the Sudanese military and a powerful paramilitary force is likely to destabilise the entire region, according to Farhan Haq, deputy spokesperson for the secretary-general.

Sudan descended into chaos after months of tension between military chief General Abdel-Fattah Burhan, and his rival General Mohammed Hamdan Dagalo, commander of the paramilitary Rapid Support Forces (RSF), exploded into open fighting in mid-April.

Health minister Haitham Mohammed Ibrahim said last month that the clashes have killed more than 3,000 people and wounded 6,000 others. The death tally, however, is highly likely to be much higher.

More than 2.9 million people have fled their homes to safer areas inside Sudan or crossed into neighbouring countries, according to UN figures.

The fighting came 18 months after the two generals led a military coup in October 2021 that toppled a Western-backed civilian transitional government.

The conflict dashed Sudanese hopes of a peaceful transition to democracy after a popular uprising forced the military removal of longtime autocrat Omar al-Bashir in April 2019.

The war has turned the capital Khartoum and other urban areas across the country into battlefields.

Residents in Khartoum said fierce fighting was under way south of the capital early on Sunday.

The warring factions were using heavy weapons in the battles in the Kalaka neighbourhood and the military’s aircraft were seen hovering over the area, said resident Abdalla al-Fatih.

In his statement, Mr Guterres also condemned an airstrike on Saturday that health authorities said killed at least 22 people in Omdurman, a city just across the Nile from the capital, Khartoum. The assault was one of the deadliest in the conflict.

The RSF blamed the military for the attack in Omdurman. The military, in turn, denied the accusation saying in a statement that its air force did not carry out any airstrikes in the city that day.

The secretary-general also decried the large-scale violence and casualties in the western region of Darfur, which has experienced some of the worst fighting in the ongoing conflict, Haq said in a statement.

“There is an utter disregard for humanitarian and human rights law that is dangerous and disturbing,” Mr Guterres said.

UN officials have said the violence in the region has recently taken on an ethnic dimension, with the RSF and Arab militias reportedly targeting non-Arab tribes in Darfur, a region consisting of five provinces.

Last month, the governor of Darfur, Mini Arko Minawi, said the region was sliding back to its past genocide, referring to the conflict that engulfed the region in the early 2000s.

Entire towns and villages in West Darfur province were overrun by the RSF and their allied militias, forcing tens of thousands of residents to flee to neighbouring Chad.

Activists have reported many residents killed, women and girls raped, and properties looted and burned to the ground.

There were clashes between the military and the RSF elsewhere in Sudan on Sunday including in the province of North Kordofan, South Kordofan and Blue Nile.