ESTELLE SHIRBON IMPLEMENTING the ceasefire agreed by the Ethiopian government and forces from the northern region of Tigray will be fraught with difficulties, while thorny political and territorial disputes will need to be tackled to achieve lasting peace. Two years of war between Ethiopia's federal army and Tigray forces have killed thousands of people, displaced millions from their homes, brought hunger to towns and villages across the region and caused catastrophic destruction. The truce signed on Wednesday after just a week of formal peace talks in the South African capital Pretoria reflected heavy pressures on both sides. When the talks…