Prime Minister Abiy Ahmed on Tuesday replaced the defence minister, his former ally Lemma Megersa, as part of a reshuffle ahead of elections in the heavily divided nation next year.
Lemma was replaced by Kenea Yadeta, the former security chief of Oromiya region, Abiy's office said on Twitter. Nine other top officials were also replaced, including the attorney general, his deputy and the mining minister.
Abiy has promised to hold the first free and fair elections in Africa's second most populous nation next year, but his democratic reforms have also unleashed ethnic divisions that frequently spill into violence.
Lemma was once a trusted ally of Abiy but relations soured in November after he publicly criticised Abiy's decision to consolidate the ethnically based-parties in the ruling coalition into one political party, the Prosperity Party. Last week, Prosperity Party suspended Lemma's membership.
Abiy's father and Lemma both come from Oromiya, the most populous of Ethiopia's 10 regions. Oromiya is a political weathervane: the region spearheaded the bloody street protests that propelled Abiy to power in 2018.
But Abiy's support there is being eroded. Bloody protests sparked by assassination of a popular singer killed more than 178 people there last month, triggering mass arrests.
International rights groups have also criticised the military for abuses during operations against an insurgency in western Oromiya.
Lemma's removal may further whittle away support for Abiy, said political analyst Mohamed Olad.
"Lemma enjoys wider support and approval in Oromia than Abiy," he said. "Whether he will activate that reservoir of goodwill depends on two things. First, whether he will be free to exercise his political rights ...(and) whether he is willing to play an active role in politics."
Lemma's criticism joined a growing swell of voices - some from Oromiya - who accuse Abiy of trying to centralise power and of rolling back his democratic reforms.
Kjetil Tronvoll, professor of peace and conflict studies at Bjørknes University in Oslo, told Reuters that the debate whether to centralise or devolve power was at the heart of Ethiopia's fractious politics.
"This is the key controversy in all federal arrangements - the power balance between the federal and regional states," he said.
If the Oromo youth who helped Abiy to power turn against him, it could pose a problem during the elections, Tronvoll said.
Unrest in Oromiya not Abiy's only worry. The northern Tigray region, whose people dominated the last administration, has announced it will hold regional elections this month in defiance of a government decision to postpone polls across the nation due to the outbreak of the coronavirus.