Thousands of people are feared to have been murdered in the western Sudanese city of el-Fasher, capital of North Darfur state, since the paramilitary Rapid Support Forces (RSF) seized it.

El-Fasher fell on Sunday after 18 months of RSF siege, which blocked the entry of food and essentials for hundreds of thousands of people trapped inside.

Sudan has been ravaged by a civil war for the past two-and-a-half years, causing an estimated 40,000 deaths and the displacement of 12 million people, the UN says.

Here’s what we know about the reported massacres in el-Fasher:

The RSF seized el-Fasher on Sunday, taking SAF’s last remaining positions in the Darfur region – some 2,000 people had been killed by Wednesday, according to reports.

Some 1.2 million people in the city had been under siege for 18 months, forced to survive on animal feed as the RSF built 56km (35-mile) of barriers, preventing entry of food and medicine and sealing off escape routes.

Videos shared online and verified by Al Jazeera’s Sanad verification agency showed RSF fighters executing and torturing people. RSF members have frequently recorded themselves committing atrocities in the past.

Sudanese medical and rights groups, including the Sudan Doctors Network, said the RSF was committing mass killings, detaining people and attacking hospitals.

The UN Human Rights Office said the RSF’s actions included summary executions of people fleeing, and that there were “indications of ethnic motivations for killings”.

An analysis by Yale’s Humanitarian Research Lab (HRL) appeared to confirm reports of mass killings, using satellite imagery and remote-sensing data.