Ethiopia has entered its most serious crisis since the 2020 to 2022 Tigray War. On 22 and 23 September 2026, open fighting resumed between federal forces and the Tigray People's Liberation Front (TPLF), which seized the airports at Mekelle, Axum and Shire and pushed into the Afar and Amhara regions. The fighting follows months of rising tension and the collapse of the 2022 Pretoria peace deal. It comes days after the TPLF joined six other armed groups, including its former enemy, the Amhara Fano militia, in an alliance seeking to topple Prime Minister Abiy Ahmed. This report explains who is fighting and why, and how the ceasefire collapsed. It sets out three scenarios for the months ahead, a drawn-out war being the most likely, and examines the roles of Eritrea and the Djibouti trade corridor. It closes with what the crisis means for travel, supply chains and security in the region.