UN Secretary-General António Guterres warns the Tigray conflict in Ethiopia may destabilize the entire Horn of Africa.[21] 15 November – 25,000 refugees flee from Tigray, to Sudan while the Federal Ethiopian Government invades the Ethiopian region of Tigray.[22] 17 November – Mekelle was hit by an air strike, killing two civilians and injuring several others.[citation needed] 18 November – The Prime Minister was reported as saying that the Ethiopian Army was advancing on Mekelle, and had captured the cities of Shire and Axum.[citation needed] 25 November – The Organization of African Unity sends ex-presidents Joaquim Chissano (Mozambique), Ellen Johnson Sirleaf (Liberia), and Kgalema Motlanthe (South Africa) to Addis Ababa to negotiate a peace.[23] 27 November – The first of four United Nations humanitarian flights land in Khartoum carrying 32 tons aid from the UNHCR.[24] 28–29 November – Seven to eight hundred civilians are massacred by the Ethiopian National Defense Force and Eritrean Army in the Aksum massacre.[25] 8 December – Tigray conflict: Government forces shoot at and temporarily detain representatives of the United Nations as they try to reach the Tigray Region.