CAIRO/TINE: The Sudanese paramilitary force that besieged then overran a city in Darfur in late October is systematically holding trapped residents for ransom, killing or beating those whose families cannot pay, witnesses, aid workers and researchers say.

Reuters could not determine exactly how many people the paramilitary Rapid Support Forces (RSF) and allied militias have detained in and around Al-Fashir, capital of North Darfur.

But the accounts suggest that large groups are being held in a cluster of villages within 80 km (50 miles) of Al-Fashir, while others have been brought back into the city as the RSF demands payments worth thousands of dollars from their relatives.

Their detention shows the risks faced by those who were unable to reach safety from Al-Fashir, which had been the final significant holdout against the RSF in the western Darfur region before its fall.

Witnesses have described mass reprisals including summary executions and sexual violence since the RSF takeover.