Traumatised civilians left in El-Fasher, Sudan, after its capture by paramilitary forces are living without water or sanitation in a city facing famine, UN aid coordinator Denise Brown told AFP on Monday.

El-Fasher fell to the paramilitary Rapid Support Forces (RSF) in October after more than 500 days of siege, and last Friday a small UN humanitarian team made its first visit in nearly two years.

Brown described the city as a "crime scene," but said investigations would be carried out by human rights experts while her office focuses on restoring aid to the survivors.

"We weren't able to see any of the detainees, and we believe there are detainees," she said.

From a humanitarian point of view, she said, El-Fasher remains Sudan's "epicentre of human suffering," and the city, which once held more than a million people, is still facing famine.

"We don't have enough information yet to conclude how many people remain there, but we know large parts of the city are destroyed. The homes of the people who remain have been destroyed," she said.

"These people are living in very precarious situations," warned Brown, a Canadian diplomat and the United Nations' humanitarian coordinator in Sudan.

Since April 2023, Sudan has been gripped by a conflict between the regular army and its former allies, the RSF, that has triggered a humanitarian catastrophe.

Brown said that the team "negotiated hard with the RSF" to obtain access, and managed to look around and visit an overburdened hospital and some abandoned UN premises — but only for a few hours.