At least 50 people have been killed in a single attack by Sudanese paramilitaries who have besieged and raided villages in al-Jazira state, activists said.

The paramilitary Rapid Support Forces (RSF) have been at war with Sudan's regular army since April 2023 but have in recent days intensified their violence against civilians in al-Jazira, south of the capital Khartoum, after their commander in the state defected to the army.

"The villages of al-Sariha and Azraq have been under attack" since Friday morning, the resistance committee in Hasaheisa, one of the hundreds of volunteer groups coordinating aid in Sudan, said in a statement late on Friday.

In al-Sariha alone, the attack killed 50 and wounded more than 200, the resistance committee added, reporting a total "inability to evacuate the wounded from the village due to the shelling and snipers" from the RSF.

With a near-total communications blackout, tolls are impossible to verify and often hard to gather.

The resistance committee said that the nearby village of Azraq had been placed under a "total siege, suffering the same violations as al-Sariha," although it was not possible to provide a death toll.

On Friday, the Sudanese doctors' union called on the United Nations to press for safe humanitarian corridors into villages that "are facing genocide at the hands of the Rapid Support militia."

The doctors' union added that rescue operations had become impossible and that "the army is incapable of protecting civilians."

According to medical sources in several villages, nearly all health facilities capable of receiving emergency cases have been forced shut.

The war in Sudan has killed tens of thousands of people, with some estimates of 150,000 dead.

It has also caused what the UN calls the world's largest displacement crisis, with more than seven million uprooted.

In June, Linda Thomas-Greenfield, the United States ambassador to the UN, said Sudan is the planet's "largest humanitarian crisis."

Famine was declared in July in the Zamzam camp for displaced people near the town of El-Fasher, in Sudan's western Darfur region bordering Chad.

Last Sunday the army announced that the RSF's al-Jazira commander Abu Aqla Kaykal had abandoned the paramilitaries, bringing "a large number of his forces" with him, in what it said was the first high-profile defection to its side.

Activists reported at least 20 people killed in subsequent paramilitary attacks in eastern al-Jazira. They also said an air strike by the Sudanese Armed forces on a mosque in the state capital, Wad Madani, killed 31 people.

On Thursday, neighbouring Chad denied helping to arm the paramilitaries after the governor of Sudan's Darfur region, Minni Minnawi, accused them of doing so.

"Chad has no interest in amplifying the war in Sudan," said Chadian Foreign Minister Abderaman Koulamallah, pointing out that Chad was "one of the rare countries upon which this war has had major repercussions."

Sudanese authorities have previously charged that Chad was facilitating the delivery of weapons from the United Arab Emirates to Sudan, which both Chad and the UAE have denied.

The International Monetary Fund's director for Africa, Catherine Pattillo, said this week that the war in Sudan was likely to cause heavy economic damage to its already struggling neighbours.

"And then to be confronted with the refugees, the security issues, the trade issues, is very challenging for their growth," she said. (AFP)