Ethiopia has accused Eritrea of an "all‑out invasion" of its northern Tigray region and warned it will defend itself, days after residents told the BBC Eritrean troops had crossed into the country.

In a letter to the UN Security Council, Ethiopia’s foreign minister described the incursion as a “blatant act of aggression” that secures Ethiopia’s inherent right to self‑defence.

Eritrea’s Information Minister, Yemane Gebremeskel, said Ethiopia was “facing an unprovoked war of aggression” and that its forces had moved up to 60km (37 miles) into Tigray.

The conflict between the government and the Tigray People’s Liberation Front (TPLF) — which began two weeks ago — has strained relations and led to the severing of diplomatic ties last week.

During the two‑year civil war, Eritrea fought alongside the Ethiopian government against the TPLF, but after the 2022 peace deal both sides blame each other for renewed fighting.

Ethiopian drone strikes reportedly hit Eritrean forces in Adigrat on Wednesday and Thursday, with several lorries destroyed and the forces retreating northward.

The UN letter, dated 8 October, called for international understanding and support as “in this time of difficulty, when Ethiopia is left with no other option than to defend itself”.

Eritrea refuted the accusations, branding them as duplicitous and accusing Ethiopia of attempting regime change by supporting opposition mercenaries.

The situation follows months of tensions and the launch of a new armed alliance involving the TPLF in September.

With Mekelle back under government control, the region remains volatile as both sides continue to mobilise.