The African Union said it was following events in the Ethiopian region of Tigray with "deep concern", as tensions between rival factions threaten a fragile peace agreement.

"The African Union (AU) has been closely monitoring the evolving situation within the Tigray People's Liberation Front (TPLF) with deep concern," it said in a statement on Friday.

A peace agreement in 2022 ended a brutal two-year war between Tigrayan rebels and the federal government that claimed up to 600,000 lives, according to some estimates.

But a failure to fully implement the terms has fuelled divisions within the Tigrayan political elite and combined with deteriorating ties between Ethiopia and neighbouring Eritrea to raise fears of a new conflict.

"The AU emphasises that adherence to the (2022 peace agreement) is crucial for maintaining the hard-won peace and fostering an environment conducive to sustainable peacebuilding, reconciliation and development," the statement said.