The response by Eritrean Information Minister Yemane Gebremeskel on X followed a letter from Ethiopian authorities to members of the United Nations Security Council, seen by AFP, accusing Eritrea of "a blatant act of aggression" after Eritrean troops were spotted in the northern Tigray region in recent days.

The two neighbours have traded accusations of interference and aggression over the past week, amid mounting tensions in the Horn of Africa, and have severed diplomatic ties.

"Ethiopia's Ministry of Foreign Affairs is these days accusing Eritrea for acts of 'unprovoked aggression that may jeopardize regional peace and security'," Gebremeskel wrote on X.

"Audacity and duplicity in their most extreme forms," he added.

Gebremeskel accused the Ethiopian government of pursuing "an unprovoked war of aggression against Eritrea for more than three years", in violation of international law and the UN Charter, which prohibit the use of force against another state's sovereignty and territorial integrity.

He cited a statement by Ethiopia's prime minister to parliament on 13 October 2023, saying: "Ethiopia has in essence declared a war of aggression against Eritrea" by announcing its intention to secure "sovereign access to the sea, through negotiations if possible and by force if necessary".

Landlocked Ethiopia has repeatedly called for direct access to the sea, a demand Eritrea views as a threat to its sovereignty and a possible attempt to seize its Red Sea port of Assab.

"The hysterical infatuation with the Red Sea must also be seen with previous intentions to wage a war of invasion against Eritrea," Gebremeskel said.

He also accused Ethiopia of invoking Israel's annexation of the Golan Heights as a precedent for its ambitions regarding Assab port.

Eritrea gained independence from Ethiopia in 1993. The two countries fought a devastating border war from 1998 to 2000.

Relations improved after Abiy Ahmed became Ethiopian prime minister in 2018, and Eritrea fought alongside Ethiopian forces during the 2020-2022 war against the Tigray People's Liberation Front (TPLF).

But relations have since deteriorated, with Eritrea dissatisfied with the outcome of the Tigray war and increasingly concerned about the prospect of an Ethiopian invasion.