GUILIA PARAVICINI AN escalating conflict in Ethiopia's restive Tigray region has killed hundreds of people, sources on the government side said, even as the prime minister sought to reassure the world his nation was not sliding into civil war. The flare-up in the northern area bordering Eritrea and Sudan threatens to destabilise Africa's second-most populous nation, where ethnic conflict has already killed hundreds since Prime Minister Abiy Ahmed took over in 2018. Reuters reporters travelling in Tigray and the neighbouring Amhara region saw trucks packed with armed militia and pickups with mounted machine-guns rushing to the front line in support…