Also joining the war front is distance runner Feyisa Lilesa, who became famous for his protest at the 2016 Rio Olympics for crossing his wrists over his head - a sign showing anger against how the government was treating the Oromo people.

Several high-profile Ethiopians have made similar announcements as fighting intensifies and rebels saying they are advancing towards the capital Addis Ababa.

This comes as photographs emerged online of Mr Abiy heading out to war dressed in military fatigues in a convoy surrounded by special forces.

It’s not clear if the PM has already joined the fighting as the BBC can't independently verify the photographs.

Mediations being led by African Union’s envoy, Olusegun Obasanjo, have yielded little progress.

On Tuesday, US envoy to the region, Jeffrey Feltman, warned that tentative diplomatic progress towards ending the conflict was being jeopardised by alarming developments on the ground.

The year-long conflict has led to a humanitarian crisis, with thousands of people killed, millions displaced and hundreds of thousands facing famine-like conditions.

Several countries including the US, France and Turkey have asked their nationals to leave the country immediately.