Tigrayan forces fighting the central government say they have withdrawn from neighbouring regions in northern Ethiopia, a step towards a possible ceasefire after 13 months of brutal war.

“We trust that our bold act of withdrawal will be a decisive opening for peace,” wrote Debretsion Gebremichael, the head of the Tigray People’s Liberation Front (TPLF), the political party controlling most of the northern region of Tigray, in a letter to the United Nations on Monday.

His letter called for a no-fly zone for hostile aircraft over Tigray, imposing arms embargoes on Ethiopia and its ally Eritrea, and a UN mechanism to verify that external armed forces had withdrawn from Tigray.