FORCES of Ethiopia's Tigray People's Liberation Front (TPLF) have destroyed an airport in the ancient town of Axum, state-affiliated media has announced, after advancing federal troops gave them a 72-hour ultimatum to surrender. Prime Minister Abiy Ahmed has told the TPLF, which had been ruling the mountainous northern zone of 5 million people, to lay down arms by Wednesday or face a final assault on the regional capital Mekelle. TPLF leader Debretsion Gebremichael told Reuters that the threat was a cover for government forces to regroup after what he described as defeats on three fronts. There was no immediate response…