ADDIS ABABA: Tigrayan rebels in northern Ethiopia seized control of airports and battled federal troops in the neighbouring Afar region, multiple sources told AFP on Wednesday, as long-standing tensions spilled into open conflict.

The Tigray People's Liberation Front (TPLF) fought a devastating civil war with the federal government in 2020-2022 that killed some 600,000 people, according to African Union estimates.

Sporadic clashes and drone strikes in recent months have raised fears of a return to war.

Two humanitarian staff working in the Afar region told AFP that fighting broke out in the towns of Abala and Erebti late Tuesday between the TPLF and federal forces.

"We are expecting it to expand. We just sent a truck with food to help the people displaced," one said, requesting anonymity.

A foreign security source in Ethiopia confirmed the clashes and said the TPLF was in control of Abala.

Abala is located in mountain ranges that mark the border with Tigray, and federal forces have been based there in recent months. Erebti lies around 100 kilometres (60 miles) further into Afar.

A former TPLF senior official told AFP the rebels were in control of Berhale, Erebti, Abala, Megale, Dalul and Konoba in Afar, though this could not be confirmed by AFP.

The federal forces are "fast-retreating", he said.