A 2020-22 civil war between the Tigray People's Liberation Front (TPLF) and federal forces resulted in hundreds of thousands of deaths before the Pretoria Agreement was signed in November 2022.
The outbreak of new fighting follows months of growing animosity between the two sides, capped by Sunday's announcement that the TPLF had formed an alliance with six other armed groups from across Ethiopia aimed at overthrowing Prime Minister Abiy Ahmed's government.
"Following the intensification of the invasion conducted through various methods by Abiy Ahmed's autocratic and genocidal Prosperity regime against the people of Tigray ... the Tigray National Regional Government announced that the Tigray Forces have been instructed to counter the attack and have entered a defensive war," the TPLF-led regional administration said in a statement on Wednesday.
Getachew Reda, an adviser to Abiy and a former TPLF official, wrote on X that the TPLF had seized control of federally controlled airports in Tigray and launched an "all out offensive" against government positions in the neighbouring regions of Afar and Amhara.
Ethiopian Airlines suspended flights to the region.
Four sources, including a senior Ethiopian government official, a diplomatic source, a humanitarian source and another source with links to the TPLF and an allied militia, confirmed the developments in Tigray, Afar and Amhara.
They said that in Afar, Tigrayan forces were fighting alongside a local armed group, and that in Amhara, they were fighting alongside the Fano militia.
Fano sided with the federal government during the 2020-22 war, but rose up against it in 2023.
It is a member of the new alliance with the TPLF.
Spokespeople for Abiy, the federal government and the TPLF did not immediately respond to requests for comment on Wednesday.
The federal government has accused the TPLF of violating the Pretoria Agreement and seeking to create chaos.
Abiy's spokeswoman, Billene Seyoum, told Reuters on Monday that members of the newly announced alliance had been collaborating for a while with the financial backing of Ethiopia's neighbour and historic adversary Eritrea.
Eritrea has repeatedly denied accusations it supports Ethiopian armed groups. Its information minister declined to comment on Wednesday about the latest developments.
