The UN Office for the Coordination of Humanitarian Affairs (OCHA) said in a statement to AFP that the attack at midnight Friday in the town of Dedebit in northwestern Tigray had "caused scores of civilian casualties including deaths", according to its preliminary information.

"Humanitarian partners suspended activities in the area due to the ongoing threats of drone strikes," it said.

Tigray rebels said Saturday that the attack had killed 56 people, but it was not possible to independently verify the claims because access to war-hit Tigray is restricted and it remains under a communications blackout.

The strike came the same day that the Ethiopian government announced an amnesty for several senior officals from the rebel Tigray People's Liberation Front (TPLF) and other high-profile opposition leaders in a bid to foster "national reconciliation".

OCHA said the lack of essential supplies, especially medical supplies and fuel, was "severely disrupting the response to the injured, and (has) led to the nearly total collapse of the health system in Tigray".

"The intensification of air strikes is alarming, and we once again remind all parties to the conflict to respect their obligations under international humanitarian law," it said.