The blood is visible from space as bodies pile up from a slaughter unprecedented in recent times.

Surrounded by a sand barrier built during an 18-month siege, most of the 250,000 people in el-Fasher, in western Sudan , have been trapped as paramilitary fighters from the Rapid Support Forces (RSF ) have rampaged through the city. Experts estimate tens of thousands have been killed in the past week.

With the key regional capital under a communications blackout, it has been left to eyewitness accounts as well as satellite imagery and video shared on social media to reveal the scale of what is unfolding in el-Fasher and the surrounding Darfur region, prompting humanitarian organizations to warn that the northeast African nation is returning to its genocidal past.

NBC News spoke to one

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