Eritrea's foreign ministry stated on Thursday that it was severing all diplomatic ties with Ethiopia, marking a sharp escalation in tensions between the neighboring countries.

The move came hours after Ethiopia announced it would close its embassy in Asmara and declared 10 Eritrean diplomats, including the charge d'affaires, persona non grata. Ethiopian officials accused the diplomats of involvement in activities threatening national security and gave them 48 hours to leave the country.

Eritrea described the Ethiopian actions as an effective closure of its own embassy in Addis Ababa and said it had no option but to reciprocate. The Eritrean foreign ministry said in a statement that the decision carried "all the negative corollaries that this entails."

Addis Ababa has accused Eritrea, along with Sudan and Egypt, of supporting an opposition alliance led by the Tigray People's Liberation Front that has fought Ethiopian federal forces since last week. The alliance includes seven armed groups seeking to overthrow the government of Prime Minister Abiy Ahmed.

Eritrea denies the accusations. Fighting has intensified in northern Ethiopia, with Tigrayan forces seizing airports in the region and clashing in neighboring Afar and Amhara states. Reports also emerged of explosions and possible drone strikes in Addis Ababa targeting military sites.

The diplomatic rupture revives strains between the two nations that had briefly improved after the 2018 peace agreement that earned Abiy the Nobel Peace Prize. Eritrea backed Ethiopian federal forces during the 2020-2022 Tigray war but was excluded from the subsequent Pretoria ceasefire. Relations have since deteriorated over Ethiopia's push for Red Sea access, including rhetoric about the Eritrean port of Assab.

Hundreds have been killed or wounded in the latest round of clashes, raising fears of a return to the scale of the earlier civil war that claimed an estimated 600,000 lives. Ethiopian Prime Minister Abiy Ahmed is scheduled to be sworn in for a new term on Monday following June elections.

Regional analysts note the risk that the internal Ethiopian conflict could draw in neighboring states and intersect with other Horn of Africa instabilities, including Sudan's civil war.