"An RSF force carried out a horrific massacre, executing 31 people from the Al-Salha area, including underage children, in the deadliest documented mass killing the area has ever witnessed," the Sudanese Doctors Network, a volunteer group, said in a statement.

"We consider this mass execution a war crime and a crime against humanity. We call on the international community to act urgently to save the remaining civilians and to open safe corridors to allow them to leave Al-Salha, which is home to thousands of unarmed civilians," it added.

Meanwhile, the Central Resistance Committees of Al-Salha, another volunteer group, also reported the killing, saying that the militia abducted unarmed civilians from the area and executed them.

"Available data suggests that the number of civilians killed exceeds 30," the group noted.

The Emergency Lawyers Initiative, a third volunteer group, also condemned the killing, calling it "a brutal crime and a grave violation of all international conventions, amounting to war crimes and crimes against humanity."

Videos shared by soldiers wearing RSF uniforms showed detainees sitting on the ground before being shot. In the footage, one soldier was heard saying, "We will leave no prisoners anymore."

The RSF currently controls the Al-Salha area, situated in southern Omdurman, which has seen frequent clashes between the Sudanese Armed Forces (SAF) and the RSF. The RSF has not yet responded to the allegations.

Sudan has been mired in conflict between the SAF and RSF since mid-April 2023, a war that has resulted in tens of thousands of deaths, with the exact toll unknown. The International Organization for Migration estimates that the conflict has displaced over 15 million people, both within Sudan and abroad.

At least 31 civilians were killed by the paramilitary Rapid Support Forces (RSF) in Omdurman, north of the Sudanese capital Khartoum (AP Photo/Hussein Malla, File)