New outburst of violence in North Darfur state has left at least 40 people dead, activists and residents say.

Fighting intensified in Khartoum after a ceasefire deal expired and a new outburst of violence took hold in Sudan’s restive Darfur region with dozens reportedly killed in what was described as “complete lawlessness”.

Black smoke billowed above the capital on Sunday after the truce between Sudan’s army and the paramilitary Rapid Support Forces (RSF) expired hours earlier, live television footage showed.

“In southern Khartoum we are living in terror of violent bombardment, the sound of anti-aircraft guns and power cuts,” said 34-year-old resident Sara Hassan by phone. “We are in real hell.”

Fighting in the capital has led to widespread damage and looting, a collapse in health services, power and water cuts, and dwindling food supplies.

The RSF claimed it shot down a fighter jet after the army “launched an audacious airborne assault upon our forces’ positions” in northern Khartoum.

A military source said a Chinese-made jet crashed near Wadi Seidna base north of Khartoum because of a “technical malfunction”.

Witnesses said they saw an aircraft travelling from the south to the north of the capital with flames erupting from it. Others spoke of air strikes on RSF positions in the east of the city, with some civilian casualties reported.

Among the other areas where fighting was reported were central and southern Khartoum and Bahri, across the Blue Nile to the north.

Brokered by Saudi Arabia and the United States, the ceasefire calmed the street battles slightly and allowed limited humanitarian access, but like previous truces was repeatedly violated. Talks to extend the ceasefire broke down on Friday.

The deadly power struggle that erupted in Sudan on April 15 has triggered a major humanitarian crisis with more than 1.2 million people displaced within the country and another 400,000 fleeing into neighbouring states.

It also threatens to destabilise the region as a whole.

‘Completely out of control’

Beyond the capital, deadly fighting also broke out in the Darfur region in the far west of Sudan, already grappling with long-running unrest and huge humanitarian challenges.

Witnesses reported heavy fighting on Friday and Saturday had brought chaos to Kutum, one of the main towns and a commercial hub in North Darfur.

At least 40 people were killed and dozens more wounded, including residents of the Kassab camp which houses people displaced by earlier unrest, said the Darfur Bar Association, which monitors rights in the region.

The army denied claims that the RSF, which developed out of Darfur militias and has its power base in the region, had taken over Kutum.

Darfur Governor Mini Minawi – a former rebel leader now close to the army – on Twitter denounced “looting” by armed groups, declared Darfur a “disaster zone”, and appealed for help from the international community.

The governor of West Darfur, Khamis Abakar, said on Sunday there was “complete lawlessness” in his state. “Armed men have taken over everything, and the situation is completely out of control,” he said.

Saudi Arabia and the United States said they were continuing to engage daily with delegations from the army and the RSF, which had remained in Jeddah even though talks to extend the ceasefire were suspended last week.

“Those discussions are focused on facilitating humanitarian assistance and reaching agreement on near-term steps the parties must take before the Jeddah talks resume,” the two countries said in a statement.

RSF leader Mohamed Hamdan Dagalo, known as Hemedti, said in a Facebook post he had spoken by phone to the Saudi foreign minister to discuss Jeddah mediation efforts.

Hemedti’s whereabouts are unclear, although he appeared in video footage with his troops in central Khartoum earlier in the fighting.