Ethiopia’s prime minister was feted by the international community as a reformer and a peacemaker. Now, as the Guardian’s Jason Burke explains, he has launched a major military campaign in the north of his country that threatens the stability of the region

Just over a year ago, Ethiopia’s prime minister, Abiy Ahmed, was the toast of the international community. His peacemaking efforts with neighbouring Eritrea had been recognised with a Nobel peace prize and his domestic reforms were winning plaudits. This month, however, it is a different story.

The Guardian’s Africa correspondent Jason Burke tells Rachel Humphreys that Abiy Ahmed has launched a major military operation in the northern region of Tigray and imposed a state of emergency. He said he was responding to an attack on an army base by the region’s ruling party, the TPLF, which it has denied. On Saturday, government forces declared victory in the offensive after claiming to have entered the regional capital, Mekelle.