Fighting has broken out again in Ethiopia's Tigray region, threatening to reignite what may be the deadliest war of this century — bad news for the whole Horn of Africa.

• On Saturday, government troops clashed with the Tigray rebel group TPLF along the contested western edge of Tigray, the most serious breach yet of a three-year-old peace deal.
• Reporting is thin, but government forces appear to have pushed the rebels back quickly, and the fighting had calmed by Sunday.
• The last Tigray war, from 2020 to 2022, may have killed 600,000 people, mostly civilians, and the peace deal never settled who controls western Tigray.
• Neither side looks ready for full war: the rebels are weakened, while Ethiopia's army is already stretched fighting insurgencies in two other regions.
• The bigger danger is spillover — Eritrea is now cozying up to the rebels, and Ethiopia is tangled in Sudan's civil war, so a wider regional conflict could erupt.

Outlook: The next few days will show whether this was a limited border clash or the start of a broader war, with a narrow window left for a deal to pull the region back.