A senior UN official in Sudan says she is deeply troubled by reports of "atrocious crimes" in the central Gezira state, including the mass killing of civilians by the paramilitary Rapid Support Forces (RSF).
Clementine Nkweta-Salami's comments came after an activist group said that at least 124 people were killed by the RSF in attacks on villagers over the past week.
The RSF has denied targeting civilians, saying its fighters are clashing with militias armed by the military.
The 18-month conflict in Sudan has killed tens of thousands of people and displaced more than 11 million.
Gezira state turned into a major battleground last week after the RSF suffered a major blow when one of its commanders, Abu Aqla Kayka, defected to the military.
The army said he had brought "a large number of his forces" with him, in what it described as the first high-profile defection to its side.
In response, the RSF said its fighters would defend themselves and "decisively deal with everyone carrying arms".
Nkweta-Salam, the UN Resident and Humanitarian Coordinator in Sudan, said that preliminary reports suggested that the RSF had carried out a major attack across the state between 20 and 25 October.
She added that it led to mass killings, the raping of women and girls, the widespread looting of markets and homes and the burning down of farms.
Ms Nkweta-Salam said the "atrocious crimes" were on a scale similar to those seen in Sudan's Darfur region last year, when the RSF was accused of "ethnic cleansing" communities seen to be opposed to it. Ms Nkweta-Salam said the death toll was still unclear, but preliminary reports suggested that scores of people were killed in Gezira state.
In a statement on Saturday, the Wad Madani Resistance Committee, which campaigns for an end to the conflict and democratic rule in Sudan, said the RSF was committing "extensive massacres in one village after another", the Reuters news agency reported.
The Sudanese doctors' union called on the UN to push the two sides in the conflict to agree to safe humanitarian corridors into villages that were facing "genocide" at the hands of the RSF.
The doctors' union added that rescue operations had become impossible and that the army was "incapable" of protecting civilians.
New wave of mass killings
The conflict in Sudan broke out in April 2023 after a fall out between the commanders of the RSF and military, Gen Mohamed Hamdan Dagalo Gen Abdel Fattah al-Burhan respectively.
The two had jointly staged a coup in 2021, derailing to Sudan's transition to democracy, but then got involved in a vicious power struggle.
The two leaders have refused to sign a peace deal, despite efforts by the US and Saudi Arabia to broker an end to the conflict.
