NEW YORK: UN chief Antonio Guterres is "deeply concerned" over reports of a deadly airstrike in Ethiopia's Tigray region, his spokesman said Monday, in the international body's first comment on an attack which rebels said left 56 people dead.

The Tigray People's Liberation Front (TPLF) last week claimed that dozens had been killed in a drone strike on a camp for civilians displaced by the war in northern Ethiopia, in an attack that prompted aid agencies to suspend operations in the region.

Saturday's raid came only hours after the Ethiopian government had issued a call for "national reconciliation", and sparked renewed appeals from an alarmed international community for an end to the conflict.

"The Secretary-General is deeply saddened by reports that more than 50 civilians have been killed and injured in an airstrike in northern Ethiopia at midnight on 7 January," Stephane Dujarric, spokesman for the UN Secretary-General, said in a statement.

"The United Nations and its humanitarian partners are working with authorities to urgently mobilize emergency assistance in the area, despite continuing challenges due to severe shortages of fuel, cash and supplies across Tigray," he added.

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"The Secretary-General is deeply concerned about the impact the conflict continues to have on civilians in Ethiopia. He expresses his deepest condolences to the victims and their families."

AFP was not able to independently verify the various claims because access to the region is restricted and it remains under a communications blackout. Requests for comment from Ethiopian government officials went unanswered.

The attacks came just days after UN officials reported that another airstrike in Tigray had killed three Eritrean refugees, including two children.

Tigray is under what the UN has called a de facto blockade that is preventing life-saving food and medicine from reaching its six million people, including hundreds of thousands in famine-like conditions.