Ethiopia denounced Thursday a "destructive alliance" unveiled this week between rebels from war-torn Tigray and a group from Oromia, the country's largest region.
At a press conference Thursday, Prime Minister Abiy Ahmed's spokeswoman Billene Seyoum noted that lawmakers in May formally designated both the Oromo Liberation Army (OLA) and the Tigray Peoples Liberation Front (TPLF) terrorist organisations.
"This is not surprising for the federal government," Billene said of reports the two groups were joining forces.
"The government has been indicating for over two years now that the TPLF has been using Shane as errand runners for their destructive mission," she said.
The Oromia group - which calls itself the Oromo Liberation Army (OLA) but which federal officials refer to as OLF-Shane - went public with the purported alliance on Wednesday, telling AFP "the agreement is at a very early stage".
"It is based on the mutual understanding that (Prime Minister Abiy Ahmed's) dictatorship must be removed," spokesman Odaa Tarbii said.
"At this point, we share intel and coordinate strategy."
The Tigray rebels could not be reached to confirm the agreement or describe its terms.
The two groups have acknowledged they "are working in unison leading towards destructive activities against the stability of the nation and that terrorism is a general feature of both," she added.
The OLA, believed to number in the low thousands, broke off from the Oromo Liberation Front (OLF), an opposition party that spent years in exile but was allowed to return to Ethiopia after Abiy took office in 2018.
Abiy's government has blamed the OLA for a number of recent massacres targeting ethnic Amharas, the country's second-largest group, though the militants have denied responsibility.