Violence is escalating in Ethiopia, where a leader once lauded internationally for his reform agenda and forging peace with neighboring Eritrea now faces the specter of civil war.

This month, long-simmering tensions between Prime Minister Abiy Ahmed’s government in Addis Ababa and leaders from the country’s northern Tigray region have spilled into the open. Tigrayan forces and the national military have clashed, and Amnesty International recorded evidence of an alleged massacre of civilians. Hundreds of people have been reported dead. Tens of thousands have fled as refugees to neighboring Sudan.