Sudan's brutal war has intensified since the start of the year, with surging numbers of summary executions and an increase in ethnic violence, the United Nations said Friday.
The UN rights chief Volker Turk warned in a statement of "increasing ethnicisation of the conflict" between the regular armed forces and the paramilitary Rapid Support Forces (RSF), which has gripped Sudan since April 2023.
The "forgotten" conflict has already killed tens of thousands and displaced millions.
Turk's office detailed in a fresh report how the war had expanded and intensified further during the first six months of the year, "taking on increasingly ethnic and divisive dimensions, with a devastating impact on the civilian population".
In North Darfur particularly, "violence is being directed on an ethnic basis", Li Fung, the rights office representative for Sudan, told reporters in Geneva.
"This is very, very worrying," she said.
Fung said the situation in El-Fasher, which has been under paramilitary siege for about 18 months and is the final state capital in Darfur still under the control of Sudan's army, was particularly "horrific".
"There are no safe exit routes out of the city," she said.
"Civilians are trapped in a situation of impossible choice: either stay in El-Fasher and risk bombardment, starvation and atrocities if the RSF overruns the city, or flee and face the risk of summary execution, sexual violence and abduction."
Victims and witnesses who had fled the city and the nearby Zamzam displacement camp had described to Fung and her team "systematic violations and abuses, often ethnically motivated", she said.
She highlighted accounts of "abductions and targeted sexual violence against women and girls based on their ethnic identity and perceived affiliation".
The war has effectively split the country, with the army holding the north, east and centre, while the RSF dominates parts of the south and nearly all of the western Darfur region.
The rights office said it had documented the deaths of at least 3,384 civilians in the conflict in the first six months of 2025, but acknowledged the true numbers were likely far higher.
That represents about 80 percent of the total number of killings documented in the whole of last year, it said.
Most of the civilians killed died in the hostilities, but at least 990 civilians were killed outside the fighting, including through summary executions, the office said.
It noted "a surge in summary executions" between February and April in Khartoum as government forces recaptured territory previously controlled by RSF, and "campaigns of apparent reprisals against alleged collaborators ensued".
The conflict in Sudan has created what the UN has called the world's worst humanitarian crisis, with famine declared in several areas and a severe cholera outbreak.
More than 2,500 people have already died of the acute intestinal infection in the country, the International Committee of the Red Cross said, citing figures from Sudanese authorities.
That "is a big, big number... that will certainly increase", Patrick Youssef, ICRC's regional director for Africa, told reporters in Geneva.
Turk urged a rapid end to the conflict.
"Many more lives will be lost without urgent action to protect civilians and without the rapid and unhindered delivery of humanitarian aid," he said.