Ethiopian jets bombed the Tigray region on Friday and Prime Minister Abiy Ahmed has pledged more air strikes in the escalating conflict amid reports that Tigrayan forces had seized control of federal military sites and weapons.
Civilians in the northern region should avoid "collateral damage" by not gathering outside as strikes would continue, Abiy said in a televised speech on Friday evening, defying international pleas for both sides to show restraint.
The developments illustrate how quickly the days-old conflict is escalating, raising the threat of a civil war that experts and diplomats warn would destabilise the country of 110 million people and hurt the broader Horn of Africa.
A simmering row between Abiy's federal government and his former Tigrayan allies exploded on Wednesday after Abiy ordered a military campaign.
Abiy, who won last year's Nobel Peace Prize, accused the Tigray People's Liberation Front, of attacking a federal military base and trying to steal equipment. He said "the last red line" had been crossed.
In a step to further deny legitimacy to Tigray's regional government elected in September against the federal government's advice, Ethiopia's federal parliament on Saturday approved the formation of an interim government for the region.
The government cut phone and internet communications to the region, according to the digital rights group Access Now, making it impossible to verify official accounts. The government accused the TPLF of shutting down communications.
Diplomats, regional security officers and aid workers have told Reuters that fighting is spreading in the northwestern part of the country, along Tigray's border with the Amhara region, which is backing the federal government, and near the border with Sudan and Eritrea.
Abiy said on Friday that government troops had seized control of the town of Dansha, near the border area, from the TPLF.