The United Nations secretary-general warned Tuesday that the war in Sudan is “spiraling out of control” after a paramilitary force seized the Darfur city of El Fasher.

Axar.az informs, citing CNN, speaking at a UN summit in Qatar, António Guterres offered a stark warning about El Fasher and called for an immediate ceasefire in the two-year conflict that’s become one of the world’s worst humanitarian crises.

“Hundreds of thousands of civilians are trapped by this siege,” Guterres said. “People are dying of malnutrition, disease and violence. And we are hearing continued reports of violations of international humanitarian law and human rights.”

He added that there also were “credible reports of widespread executions since the Rapid Support Forces entered the city.”

UN officials have warned of a rampage by the paramilitary Rapid Support Forces after it took over the city of El Fasher, reportedly killing more than 450 people in a hospital and carrying out ethnically targeted killings of civilians and sexual assaults.

The RSF has denied committing atrocities, but testimonies from those fleeing, online videos and satellite images offer an apocalyptic vision of the aftermath of their attack. The full scope of the violence remains unclear because communications are poor in the region.