Seven Ethiopian armed groups have formed an alliance against the federal government, an official of the Tigray People's Liberation Front (TPLF) told AFP on Sunday.
Both the government and the TPLF have massed troops along the border of the northern state in recent months, according to the African Union, fuelling fears of a return to the war that killed some 600,000 people.
"We just formed an alliance, we are collaborating with several groups and our objectives are to remove the regime and facilitating a transitional government," said TPLF vice president Amanuel Assefa.
The groups involved are Tigrayan forces, Amhara nationalist Fano militias and the Oromo Liberation Army (OLA), an active insurgency in Ethiopia's most populous region -- together with four others.
"We think we will be successful, we have been talking with each other for more than a year," said Amanuel. Fano leader Zemene Kasse will chair the alliance, he added.
The federal authorities have not yet responded to AFP's request for comment on the alliance.
Kjetil Tronvoll, a regional specialist at Oslo New University College in Norway, cast doubt on the alliance's effort to overthrow the federal government, which possesses numerous drones.
Describing it as "a sacrificial war for the rebels", he told AFP: "I am not sure they will be able to sustain such a war.
"If they coordinate as a military command, it may make a difference, it is a potential four to five fronts that the government will have to deal with, it might be a challenge," he added.
But he questioned what might come after any takeover, given the armed groups' different ideologies.
Past clashes
Ethiopia has been plagued by armed conflicts in its two most populous regions, Oromia and Amhara.
Federal forces have been fighting the OLA, which the government has designated a "terrorist organisation", since 2018 in central Oromia.
The Fano, traditional "self-defence" militias of the Amhara ethnic group, took up arms against the government in April 2023 after federal authorities moved to disarm them. The group is particularly active in rural areas.
Despite Sunday's announcement, doubts remain over an alliance between groups that have clashed in the past. Fano fought alongside Ethiopian federal forces during the Tigray war.
The groups also have territorial disputes. Western Tigray, a contested area between Amhara and Tigray, has been administered by Amhara nationalists since the end of the war.
"We will sit at the table later to solve our problems peacefully," Amanuel said.