Egypt expelled an Ethiopian diplomat on Thursday in retaliation for Addis Ababa's expulsion of an Egyptian diplomat, further straining relations between the two countries amid a widening regional crisis in the Horn of Africa.

Cairo declared a counsellor at the Ethiopian Embassy persona non grata and gave him 48 hours to leave, according to Egypt's state news agency MENA. The move came after Ethiopia ordered Egyptian diplomat Ahmed Moharam Ahmed Soliman to leave within 48 hours without publicly giving a reason.

An Egyptian official described Ethiopia's decision as "regrettable and unjustified" and said Cairo's response was based on the principle of reciprocity.

The official also rejected any suggestion that Egypt interferes in Ethiopia's internal affairs, saying Cairo refrains from commenting on developments in other countries in accordance with international law and the U.N. Charter. The official accused Addis Ababa of attributing its domestic crises to alleged foreign interference.

Ethiopia has not publicly explained the reason for expelling the Egyptian diplomat.

The diplomatic dispute adds to a long-running confrontation over Ethiopia's Grand Ethiopian Renaissance Dam (GERD), which Addis Ababa says is essential for its economic development and electricity generation.

Egypt, which depends heavily on the Nile for its freshwater supplies, has long demanded a legally binding agreement governing the dam's operation and the release of water during periods of drought. Years of negotiations involving Ethiopia, Egypt and Sudan have failed to produce such an agreement.

The dispute intensified after Ethiopia completed and inaugurated the GERD and subsequently announced plans for additional dams on the Blue Nile. Cairo has repeatedly warned that projects that could reduce or disrupt its access to Nile waters pose a serious threat to its water security.

Egyptian President Abdel Fattah al-Sisi said this week that Cairo was leaving room for diplomacy and peaceful solutions but would not accept measures that it considers threatening to Egypt's existence or its people.

The latest diplomatic confrontation comes as fighting has intensified in Ethiopia's northern Tigray region.

Ethiopia has accused Egypt, Sudan and Eritrea of supporting an opposition alliance led by the Tigray People's Liberation Front (TPLF). Egypt and Sudan have denied involvement, while Eritrea has also rejected accusations of backing forces hostile to Addis Ababa.

The crisis has also triggered a dramatic deterioration in Ethiopia-Eritrea relations. Ethiopia closed its embassy in Asmara and expelled 10 Eritrean diplomats, prompting Eritrea to sever diplomatic relations with Ethiopia. The moves came amid renewed fighting in Tigray and growing accusations between the two neighbours.

The African Union Commission on Friday urged Ethiopia, Eritrea and Egypt to exercise restraint and avoid actions or rhetoric that could further destabilize the region. It called for disputes to be addressed through diplomatic channels and peaceful dialogue.

The simultaneous deterioration of Ethiopia's relations with Egypt and Eritrea has raised concerns that the renewed fighting in Tigray could develop into a broader regional crisis, with the Nile dispute and competition over Red Sea access adding further pressure to already strained relations. (ILKHA)