Michael Koloke

According to Denise Brown, the UN's resident and humanitarian coordinator for Sudan, UN staff who visited the city last week came across only a few people living inside empty buildings and rudimentary camps.

Brown, who described al-Fashr as a crime scene, said that the UN was very concerned about those within the city who are injured or detained.

The paramilitary group, the Rapid Support Forces, or RSF, captured al-Fashr in October this year after besieging it for 18 months.

Fighting between the RSF and the Sudanese armed forces has been going on for more than two years now.

Last month, the Office of the Prosecutor of the International Criminal Court expressed alarm over reports of mass killings in al-Fashr.

For NPR News, I'm Michael Koloke in Nairobi.