The leader of Ethiopia's rebellious Tigrayan forces said on Friday that protests were breaking out in the regional capital which fell to federal troops days ago in their month-long war.

Fighting between Ethiopia's military and regional forces from the northern Tigray region is seriously destabilising the East African region and hostilities should halt, the European Union foreign policy chief said.

The leader of Ethiopia's dissident Tigray region has said that his people are "ready to die" defending their homeland, rejecting Prime Minister Abiy Ahmed's ultimatum that they surrender within 72 hours.

Forces of Ethiopia's Tigray People's Liberation Front (TPLF) have destroyed an airport in the ancient town of Axum, state-affiliated media said on Monday, as advancing federal troops gave them a 72-hour ultimatum to surrender.

African leaders attempted Monday to kickstart some kind of mediation in Ethiopia's escalating internal conflict, two days after rocket strikes on Eritrea's capital highlighted risks that fighting could spread.

The leader of the Tigray region of Ethiopia on Sunday claimed responsibility for rocket strikes on the airport in neighbouring Eritrea's capital, a move that ratcheted up fears of a wider conflict in the Horn of Africa region

Nine million people risk displacement from the escalating conflict in Ethiopia's Tigray region, the United Nations said, warning that the federal government's declaration of a state of emergency was blocking food and other aid.