Addisu Arega, an acting spokesperson for the regional state, said the suspects were accused of various crimes including incitement to violence, illegal land seizures, looting and ethnically motivated attacks, reported state-affiliated Fana Broadcasting Corporate.
Oromia, the largest and most populous regional state in Ethiopia, has been the site of nearly three years of often deadly anti-government protests by ethnic Oromos who feel marginalised by the central government.
The swearing into office of ethnic Oromo Prime Minister Abiy Ahmed in April, with his talk of reconciliation and inclusiveness, largely dampened the protest movement in Oromia.
However, a series of deadly ethnic clashes between ethnic Oromos and other groups residing in the region, believed to spring from long-simmering land disputes, has left hundreds of thousands displaced, and led to widespread calls on social media for law and order to be restored in the region.