Sudanese people are eating leaves and charcoal to survive after fleeing an attack on a camp for displaced people near the city of el-Fasher, an aid agency has told the BBC.
"The stories we've been hearing are truly horrific," Noah Taylor, the Norwegian Refugee Council's head of operations, told the BBC's Newsday programme.
People are fleeing el-Fasher for Tawila, but are dying "on arrival," Mr Taylor added.
He said that some were "dying of thirst", whilst making the 40km (25 mile) journey from Zamzam camp in "blistering" temperatures.
"We've heard stories there are still bodies on the road between el-Fasher and Tawila.
"We spoke to a family who told us of a girl who had walked on foot by herself from el-Fasher, was repeatedly raped along the journey, and then died of her wounds when she arrived in Tawila."
El-Fasher is the last city in Sudan's western region of Darfur under the control of the army and its allies. Earlier this month, the paramilitary Rapid Support Forces (RSF) attacked the nearby Zamzam camp, forcing tens of thousands to flee their makeshift shelters.
Many Zamzam residents had been there for two decades, after escaping previous conflicts in Darfur.
The RSF has been battling the army for the past two years in a war that has killed an estimated 150,000 people and forced some 13 million from their homes.
Aid agencies say it is the world's worst humanitarian crisis.
However, funding problems have led to the UN reducing the food aid it delivers to areas of Sudan hit by famine, it says.
