Ethiopia has told the United Nations it must defend itself against what it called an ‘all-out invasion’ by Eritrean forces.

Foreign Minister Gedion Timothewos wrote to the UN Security Council on October 8. He said Eritrean troops, including mechanized units, had deployed up to 60 km into northern Ethiopia.

The letter called the presence of Eritrean troops ‘a blatant act of aggression that engages Ethiopia’s inherent right to self-defence’. It asked for the world’s understanding and support.

This is Ethiopia’s first official statement on reported incursions this week. Witnesses told Reuters that Eritrean soldiers were seen in northern Ethiopia.

Eritrea rejected the claims. Information Minister Yemane Gebremeskel said Ethiopia was pursuing a war of aggression against his country.

The neighbours severed diplomatic ties on October 1. Ethiopia accuses Eritrea of backing a rebel alliance fighting federal troops in Tigray, Amhara and Afar since September 23. Eritrea denies it.

The letter marks the first time Addis Ababa has officially described the situation as an invasion. Until now, officials had spoken only of reported incursions.

The African Union has called for restraint. Regional diplomats fear a full-scale war between the Horn of Africa neighbours.