Hundreds have been killed and tens of thousands forced to flee their homes in Ethiopia, Africa's second most populous country, as federal troops battle rebels in the northern Tigray region.
The Guardian's Jason Burke explains what sparked the conflict, why it threatens to destabilise the Horn of Africa – and examines how the prime minister, Abiy Ahmed, the continent's youngest leader, has gone from winning a Nobel peace prize to presiding over a bloody conflict against the Tigray People's Liberation Front (TPLF)