The UN Security Council is due to hold its first meeting later on Tuesday to discuss the conflict in Ethiopia's northern Tigray state.
The virtual meeting comes as the Ethiopian government says its tanks are preparing to attack the Tigrayan capital, Mekelle.
It has given the Tigray People's Liberation Front (TPLF) forces, who control the city, until Wednesday to surrender.
TPLF forces are claiming they have "destroyed" one of the Ethiopian army's mechanised divisions.
Nearly three weeks of fighting has left hundreds of people dead.
A communications blackout in the region means that claims by either side cannot easily be verified.
International agencies have warned the conflict is on the brink of a deadly escalation.
The African countries affected are: Angola, Burkina Faso, Chad, Democratic Republic of the Congo, Djibouti, Eritrea, the Gambia, Guinea-Bissau, Liberia, Libya, Mauritania, Sudan, Sao Tome and Principe, Cape Verde, Burundi.