Emerging evidence of systematic killings in the Sudanese city of el-Fasher have prompted human rights and aid activists to describe the civil war between the paramilitary Rapid Support Forces (RSF) and the military as a continuation of the Darfur genocide.

The fall of el-Fasher, in the Darfur region, after an 18-month RSF siege brings together the different layers of the country's conflict – with echoes of its dark past and the brutality of its present-day war.

The RSF emerged from the Janjaweed, Arab militias who massacred hundreds of thousands of Darfuris from non-Arab populations, in the early 2000s.

The paramilitary force has been accused of ethnic killings since its power struggle with the army erupted into violence in April 2023. The RSF leadership has consistently denied the accusations - although on Wednesday its leader Gen Mohamed Hamdan Dagalo admitted to violations in el-Fasher.

The current charges are based on apparent evidence of atrocities provided by the RSF fighters themselves.

They have been sharing gruesome videos reportedly showing summary executions of mostly male civilians and ex-combatants, celebrating over dead bodies, and taunting and abusing people.

Accounts from exhausted survivors also paint a picture of terror and violence.

The situation in el-Fasher is extremely dire and there are violations taking place on the roads, including looting and shooting, with no distinction made between young or old, one man told the BBC Arabic service. He had escaped to the town of Tawila, a hub for those displaced from el-Fasher.

Another woman, Ikram Abdelhameed, told the Reuters news agency that RSF soldiers separated fleeing civilians at an earthen barrier around the city and shot the men.

And satellite images collected by Yale University's Humanitarian Research Lab show evidence of what seem to be massacre sites – clusters of bodies and reddish patches on the earth that the analysts believe could be blood stains.

El-Fasher appears to be in a systematic and intentional process of ethnic cleansing of… indigenous non-Arab communities through forced displacement and summary execution, the Yale researchers say in a report.

There is a clear ethnic element to the battle for el-Fasher, because local armed groups from the dominant Zaghawa tribe, known as the Joint Force, have been fighting alongside the army.

The RSF fighters see Zaghawa civilians as legitimate targets.

That is what many survivors of the paramilitary takeover of the Zamzam displaced persons camp next to el-Fasher reported earlier this year, according to an investigation by the medical charity Doctors Without Borders (MSF).

The army has also been accused of targeting ethnic groups it sees as support bases for the RSF in areas it has recaptured, including the states of Sennar, Gezira and some parts of North Kordofan.

Both sides have been accused of war crimes - ethnically motivated revenge attacks are part of that.

It was Sudan's military government in 2003 that weaponised ethnicity – enlisting the Janjaweed to put down rebellions by black African groups in Darfur who accused Khartoum of politically and economically marginalising them.

This pattern of violence established then has been repeated in Darfur now, says Kate Ferguson, the co-founder of NGO Protection Approaches.

The RSF has denied involvement in what it has called tribal conflicts, but Gen Dagalo, widely known as Hemedti, appeared to be hearing expressions of mounting international outrage.

He released a video saying he was sorry for the disaster that had befallen the people of el-Fasher in a war that had been forced upon us and admitted there had been violations by his forces.

However, observers have noted that similar promises made in the past were never fulfilled. Aid groups and activists warn that if the pattern of violence continues, it could lead to further atrocities.