Sudanese paramilitaries have killed more than 200 people in a three-day assault south of Khartoum, according to a lawyers’ network, while the army-backed government put the death toll at more than double that figure.

The Emergency Lawyers network, which has documented human rights abuses during 22 months of fighting between the rival security forces, said hundreds more were wounded or missing and feared drowned after the paramilitaries opened fire on villagers as they attempted to flee across the White Nile.

The foreign ministry of the army-backed government said 433 people, including children, had been killed in the attack by the paramilitary Rapid Support Forces (RSF).

The attack on the White Nile state villages of al-Kadaris and al-Khelwat, 100km (60 miles) south of the capital, sent thousands fleeing, witnesses said.

A spokesperson for the UN secretary general, António Guterres, said the world body had received “horrifying reports that dozens of women were raped and hundreds of families were forced to flee”.

Emergency Lawyers said that for three days RSF fighters had subjected unarmed civilians to “executions, kidnappings, forced disappearances and looting”.

Since the war broke out in April 2023, the army and the paramilitaries have been accused of war crimes.

The RSF also stands accused of genocide by the US for allegedly targeting non-Arab minorities in the Darfur region of western Sudan with summary executions and systematic sexual violence.

The war has killed tens of thousands of people, uprooted more than 12 million and has created what the International Rescue Committee has called the “biggest humanitarian crisis ever recorded”.

Control over the White Nile State, which extends from just south of Khartoum to the border with South Sudan, is divided by the warring parties.

The army controls the south, including the state capital, Rabak, as well as two major cities and a key military base. The RSF holds the northern parts of the state, including the villages where the latest attacks took place.

A medical source said it was nearly impossible to confirm a toll.

“Some bodies are still lying in the street, and some were killed in their homes and no one can reach them,” the source said, requesting anonymity for safety reasons.

Fighting has intensified across Sudan in recent weeks as the army attempts to reclaim full control of the capital from the paramilitaries.

On Tuesday, the Emergency Lawyers accused the army of “barbaric” assaults on civilians in east Khartoum, days after its paramilitary opposition killed six civilians in the area.

The network said that civilians in the East Nile district accused of collaborating with the RSF had been subjected to “killings, forced disappearances and arbitrary arrests” by individuals linked to the army.

The UN’s children’s agency said children in Khartoum were trapped in “a living nightmare” of indiscriminate shooting, looting and forced displacement.

Unicef said it had also received alarming reports of families being separated, with children abducted and subjected to sexual violence.

The UN human rights office said “entrenched impunity” had fuelled mass human rights violations across Sudan.

“Continued and deliberate attacks” on civilians including “summary executions, sexual violence and other violations and abuses underscore the utter failure” by both sides to respect international humanitarian law, it said in a statement on Tuesday.

The UN also called for the expansion of the international criminal court’s jurisdiction and a longstanding arms embargo to cover all of Sudan instead of just Darfur.

The vast western region, home to around a quarter of Sudan’s population, has seen escalating violence in recent weeks as the RSF seeks to consolidate its hold. The paramilitary group has intensified attacks on North Darfur state capital El Fasher, the only major city in Darfur it does not control.