The United Nations Secretary-General says Sudan is on the brink of a “full-scale civil war,” as brutal clashes between rival generals continued Sunday in the capital, Khartoum.

Antonio Guterres cautioned on Saturday night that the war is likely to destabilize the entire region.

Sudan spiraled into chaos after months of heightened tension between the military chief General Abdel-Fattah Burhan, and his rival General Mohammed Hamdan Dagalo, commander of the paramilitary Rapid Support Forces, escalated into open fighting in mid-April.

Guterres also condemned an airstrike Saturday, which health authorities report killed at least 22 people in Omdurman, a city just across the Nile from Khartoum.