Ethiopia's brutal war in Tigray has roared back to life. In barely two weeks, federal government troops and an allied militia have swept through the northern region's biggest cities and pushed all the way to the Eritrean border, reigniting a rivalry that fueled one of this century's deadliest conflicts.

Government forces and the militia, known as the Tigray Peace Forces, seized the regional capital Mekelle on October 3 after fighters from the Tigray People's Liberation Front (TPLF) withdrew, according to Al Jazeera. The advance then accelerated: Adigrat fell on October 9-10, the ancient religious city of Adwa was taken on October 11, and the historic city of Axum followed on October 12, with troops reaching Zalambessa on the Eritrean frontier the same day, according to the latest Ethiopia War Security Review from the Critical Threats Project.

The fighting erupted on September 20, when the TPLF and six other armed and political groups formed an alliance aimed at removing Prime Minister Abiy Ahmed and seized Mekelle's airport, disrupting flights and detaining federal personnel. The collapse ended nearly four years of fragile calm under the 2022 Pretoria peace agreement, which had stopped a 2020-2022 civil war that killed hundreds of thousands of people. Tigray's roughly 6 to 7 million residents are now facing electricity cuts and a near-total communications blackout, with some fleeing into neighboring Amhara and Afar, Al Jazeera reported. Drone strikes have hit towns including Adwa and Sheraro, with one strike on an Adwa hotel wounding between five and nine people.

A wider war brewing?

Ethiopia has accused Eritrea, Egypt and Sudan of arming the rebel alliance; all three deny it. Eritrea — which fought alongside Addis Ababa in the earlier war — severed diplomatic ties with Ethiopia on October 2 and wrote to the UN Security Council on October 10 accusing Ethiopia of "effectively declaring war," asking for Chapter VII measures that can include sanctions or military intervention. Isolated reports of skirmishes near the Eritrean town of Bure remain unverified, but the African Union has urged "maximum restraint" from all sides.

"This commander's remarks shed light on a new phase of this conflict," Al Jazeera Arabic's Ethiopia bureau chief Mohammed Taha Tawakel said, warning that the original TPLF still holds several towns and deep ties to Eritrea along more than 800km of shared border.

On the ground, federal officials are already planning for what comes next. Getachew Reda, a former Tigray leader now advising Abiy, promised "visible change" during a visit to newly retaken Mekelle, and the government says it intends to rule Tigray directly through a military command post for six months ahead of new regional elections. Several senior TPLF figures held in rebel custody also escaped to federally controlled Mekelle on October 12. African Union-brokered peace talks had reportedly been pencilled in for October 24 in South Africa, though it remains unclear whether the rapidly shifting front lines will allow them to go ahead.