• After nearly three months of war between Sudan's rival generals, the air strike is the latest incident to provoke outrage

Wad Madani. Conflict-torn Sudan is on the brink of a "full-scale civil war" that could destabilise the entire region, the United Nations warned Sunday, after an air strike on a residential area killed around two dozen civilians.

The health ministry reported "22 dead and a large number of wounded among the civilians" from what it described as an air strike Saturday on Khartoum's sister city Omdurman, in the district of Dar al-Salam, which means "House of Peace" in Arabic.

After nearly three months of war between Sudan's rival generals, the air strike is the latest incident to provoke outrage.

Around 3,000 people have been killed in the conflict, while survivors have reported a wave of sexual violence and witnesses have spoken of ethnically targeted killings.

There has been widespread looting, and the UN warned of possible crimes against humanity in the western region of Darfur.

A video posted by the health ministry on Facebook showed apparently dismembered bodies lying partly covered on the ground after the air strike.

The paramilitary Rapid Support Forces (RSF), fighting the regular army, claimed the "air strikes" killed 31.

Residents contacted by AFP also confirmed an air strike but on Sunday the armed forces released a statement "clarifying that the air force did not deal with any hostile targets in Omdurman yesterday".

Witnesses also reported more air strikes Sunday near the presidential palace in Khartoum and in Omdurman, as well as machine gun clashes and artillery fire in the city's south.

UN Secretary-General Antonio Guterres condemned the air strike in Omdurman, which he said "reportedly killed at least 22 people" and wounded dozens, his deputy spokesperson Farhan Haq said in a statement.

Guterres "remains deeply concerned that the ongoing war between the armed forces has pushed Sudan to the brink of a full-scale civil war, potentially destabilising the entire region", Haq said.

Civil aviation authorities have extended the closure of Sudan's airspace until July 31, with the exception of approved humanitarian and evacuation flights, Khartoum International Airport said on its Facebook page.

Meanwhile civilians began digging graves for those killed in the air Saturday's air strike, witnesses said.

Since the war began, many bodies have been left to rot in the streets in both Khartoum and Darfur, which has seen some of the most violent fighting.

'Dangerous and disturbing'

Nearly three million people have been uprooted by Sudan's fighting, including almost 700,000 who have fled to neighbouring countries, according to the International Organization for Migration.

The UN and African blocs have warned of an "ethnic dimension" to the conflict in Darfur, where the United States, Norway and Britain have blamed the RSF and allied militia for most of the widespread violations.

Concentrated in Darfur and Khartoum, fighting has also been reported in Blue Nile state near Ethiopia, which also has a history of unrest, as well as in South Kordofan state.

Residents in El-Obeid, the capital of North Kordofan and a commercial hub south of Khartoum, reported renewed fighting in their area overnight Saturday-Sunday, and then again on Sunday afternoon.

"There is an utter disregard for humanitarian and human rights law that is dangerous and disturbing," said Haq, expressing support for efforts by the African Union and East African bloc IGAD to end Sudan's crisis.

On Monday, leaders of Ethiopia, Kenya, Somalia and South Sudan -- IGAD members handling the Sudan file -- are to meet in Addis Ababa.

Sudan's army chief Abdel Fattah al-Burhan and RSF commander Mohamed Hamdan Daglo have been invited but neither side has confirmed they will attend.

Several Sudanese civilian figures are already there, however, "in order to accelerate peace efforts", said Khalid Omer Yousif, who was fired from the government in 2021 when Daglo and Burhan led a coup, before their falling out.

Egypt, a close ally of Burhan's, said it will host a summit of Sudan's neighbours on Thursday to seek an end to the conflict and its regional "repercussions", a statement from the president's office in Cairo said.

Numerous ceasefires in the war have been announced and ignored.