ADDIS ABABA (Reuters) - Ethiopia’s military has defeated local forces in the west of Tigray state, Prime Minister Abiy Ahmed said on Thursday, accusing his foes of atrocities during a week of fighting that threatens to destabilise the Horn of Africa.Rights group Amnesty International said scores and possibly hundreds of civilians were stabbed and hacked to death in the region on Nov. 9, citing witnesses. It said it had not been able to independently confirm who was responsible, but said the witnesses had blamed fighters loyal to Tigray’s local leaders. Air strikes and ground combat between government forces and the Tigray People’s Liberation Front (TPLF) have killed hundreds, sent refugees flooding into Sudan, stirred Ethiopia’s ethnic divisions and raised questions over the credentials of Abiy, Africa’s youngest leader who won a Nobel Peace Prize in 2019. “The western region of Tigray has been liberated,” Abiy said in a tweet. The 44-year-old leader comes from the largest ethnic group the Oromo and once fought with the Tigrayans against neighbouring Eritrea. With communications down and media barred, independent verification of the status of the conflict was impossible. Reuters was not able to confirm either side’s version of events or Amnesty’s reports of atrocities. There are fears the conflict may draw in Eritrea, whose government signed a peace pact with Abiy two years ago but remains hostile to the Tigrayan leadership, and weaken Ethiopia’s role in an African Union (AU) force opposing Islamist militants in Somalia. Major conflict could also hinder foreign investment in Ethiopia’s economy, which had clocked nearly double-digit annual growth for years before the coronavirus hit and is liberalizing, with multinationals particularly eyeing the telecoms sector. ‘GAPING WOUNDS’ Amnesty said that the people killed in the town of Mai Kadra in Tigray’s southwest on the night of Nov. 9 appeared to have been day labourers who were not involved in the fighting. It cited witnesses describing bodies with gaping wounds that appeared to have been inflicted with knives or machetes. “This is a horrific tragedy,” it said in a statement. “Amnesty International has not yet been able to confirm who was responsible ... but has spoken to witnesses who said forces loyal to the TPLF were responsible for the mass killings, apparently after they suffered defeat from the federal EDF forces,” it said.