An extensive earthen wall is being built around the besieged Sudanese city of el-Fasher and is intended to trap people inside, according to research from Yale University.
From satellite images, the university's Humanitarian Research Lab (HRL) has identified more than 31km (19 miles) of berms - or raised banks - constructed since May in territory outside the city occupied by the paramilitary Rapid Support Forces (RSF).
El-Fasher, under siege for more than a year, is the last major foothold in Darfur for Sudan's army, which has been battling the RSF since April 2023.
The Sudan Doctors Network has told the BBC that the RSF was intensifying its offensive there and deliberately targeting civilians.
Yesterday there was a shelling in a civilian area down in the city centre that ended up killing almost 24 civilians and injuring 55 people, among them five women, Dr. Mohamed Faisal Hassan, from the medics association, told the BBC's Newsday programme.
The attacks on the central market and a residential area were deliberate and heinous, he said.
Both sides in the conflict have been using berms as a defensive tool, but the analysis by Yale's HRL, which has been closely monitoring the conflict, suggests that the RSF is creating a literal kill box around el-Fasher.
The HRL traced the construction of the earthen walls onto a map of el-Fasher.
The physical boundary not only deepens the siege conditions but also controls who and what can enter or leave the city where about 300,000 people live.
Meanwhile, humanitarian organizations have been unable to access el-Fasher for months. The remaining civilians endure constant bombardment, food scarcity, and lack of medical care. Escape for many is nearly impossible.
The development has prompted increased calls for intervention, with local leaders appealing to international bodies to protect the civilian population.
As the RSF continues this aggressive strategy, the humanitarian situation in el-Fasher grows increasingly desperate.
