NAIROBI, Kenya — Residents in Ethiopia’s largest federal state of Oromia say dozens of civilians were killed in an attack by an armed group on Monday, the latest mass violence along ethnic lines to challenge one of Africa’s most populous countries. Two residents of Horo Guduru area of ​​restive Wollega district said the armed group from the Amhara ethnic community, known as Fano, indiscriminately targeted Oromos. “These Fano militias came out in full force and killed anyone they found,” a witness told The Associated Press, speaking on condition of anonymity for fear of reprisals. He said he saw six fresh bodies in a cemetery. The militants burned houses, looted cattle and threatened to return and “finish us all,” he said. Another witness said he saw about 20 bodies on Tuesday and said he believed “many more bodies remain to be discovered”. Both witnesses said the attack occurred a day after Oromia regional forces withdrew from the area. A spokesman for Ethiopia’s federal government, Legesse Tulu, hung up the phone without answering questions. The Oromia police chief did not respond. On Thursday, Ethiopia’s Media Authority issued a warning to private media outlet Finfinnee Integrated Broadcast for reporting the killings and accused it of spreading “false and unconfirmed reports”. Ethiopia has experienced widespread ethnic rivalry and conflict since Prime Minister Abiy Ahmed took power in 2018. The Fano militia has been a major player in Ethiopia’s Tigray conflict that erupted in the north of the country in November 2020. Fighting alongside the Ethiopian army, they have been involved in some of the worst atrocities committed against ethnic Tigrayians. But when that conflict calmed down in recent months, many of Fano’s leaders and members became targets of Ethiopian authorities after the prime minister branded them an “irregular force”. Earlier, Amhara nationals were targeted in the Wollega district where Monday’s killings took place. In June, hundreds of ethnic Amharas were killed and local authorities blamed the Oromo Liberation Army. The armed group denied this and blamed government forces.