Satellite images show how Sudan's paramilitary Rapid Support Forces (RSF) is flouting international law by intentionally targeting civilians in the besieged city of el-Fasher - actions that should be considered war crimes, a research team from Yale University says.

"We're looking at the growth of an entire new burial area with over 60 new mounds that have been built in just a two-week period," Caitlin Howarth, from the university's Humanitarian Research Lab (HRL), told the BBC.

People are now completely trapped with no hope of escape as the RSF recently completed a 57km (35-mile) earthen wall around the city.

Desperate residents in the army's last stronghold in Darfur say food has run out.

"There is nothing left to eat today - all food supplies have run out," the resistance committee for el-Fasher, made up of local citizens and activists, said in a statement on Tuesday.