Between 1998 and 2000, Ethiopia and Eritrea fought a devastating war that left between 70,000 and 100,000 people dead. The developments that have brought the two countries to the brink of renewed conflict are complex, rooted in the rise of Abiy Ahmed to the premiership in April 2018 and the shifting relationships between his government, rival factions within Ethiopia and the Eritrean government.
Abiy’s accession to power marked the end of a long period of dominance by the Tigray People’s Liberation Front (TPLF) in Ethiopian national politics. The subsequent struggle between the federal government and the TPLF culminated in a disastrous two-year war, fought between November 2020 and November 2022, in which as many as half a million people may have died.
In July 2018, Ethiopia and Eritrea signed a joint declaration restoring full diplomatic and commercial ties, 18 years after the Algiers Agreement formally ended their war. Four years later, Ethiopia’s federal government and the TPLF signed their own peace agreement in Pretoria. Today, the rapprochement between Ethiopia and Eritrea is under severe strain, while the Pretoria agreement has never been fully implemented, leaving territorial disputes, the return of displaced people and disarmament unresolved.
The deterioration in relations between Addis Ababa and the TPLF has been marked by a rapid succession of recent events. A key turning point came on 20 September, when the TPLF and six other regionally based armed groups—including the Oromo Liberation Army, the Amhara Fano National Movement and four smaller organisations—announced the formation of an Alliance for Survival. Its stated objective was to bring down Abiy Ahmed’s government, a development that the federal authorities would regard as the formation of an armed insurrection.
On 23 September, the TPLF attacked positions held by Ethiopia’s federal armed forces, which responded with an offensive of their own. The operation culminated in the capture of Mekelle, the Tigray regional capital, on 3 October. The TPLF withdrew to the northern parts of the region, which border Eritrea. Four months of mediation efforts by the African Union, headquartered in Addis Ababa, had evidently failed to produce the desired results. In what appeared to be an attempt to bring the region under federal control, the government installed a caretaker administration in Mekelle on 16 October, tasked with preparing for regional elections.
Eritrea, meanwhile, has been deeply unhappy with the 2022 peace agreement between the Ethiopian federal government and the TPLF, believing that its concerns over territorial integrity were ignored. Asmara has threatened to change sides and join the TPLF and its allies in their campaign to topple Abiy’s government. Ethiopia has also accused Eritrea of sending troops into Tigray to assist the TPLF, in violation of the countries’ peace arrangements and their international border. These allegations warrant serious scrutiny, although the two governments offer sharply different accounts of the situation, as reflected in letters they sent to the United Nations Security Council in early October outlining their grievances.
More alarming still, both countries reportedly decided on 1 October to sever diplomatic ties, close their embassies and send diplomatic staff home. Such measures heighten the risk of the two countries sliding once again into full-scale war.
Another source of tension is Abiy’s stated ambition to secure a seaport for Ethiopia, which has been landlocked since Eritrea became independent in 1993. Eritrea views this rhetoric as a possible prelude to an attempt to seize Assab, its southern port on the Red Sea, or even Massawa, the country’s principal central port city near Asmara. The wider maritime environment is already volatile, with attacks by Yemen’s Ansar Allah movement threatening shipping through the Red Sea. Meanwhile, increasingly belligerent rhetoric from Ethiopia’s leadership has fuelled fears that its ambitions may extend beyond access to the sea towards territorial control.
The potential consequences extend well beyond the two countries. Martin Plaut, a veteran former BBC correspondent and long-time observer of the region, has warned that an Ethiopian military incursion into Eritrea could trigger a wider regional conflagration. Eritrea’s armed forces, estimated at 350,000 personnel, would face an Ethiopian military reportedly numbering around half a million troops and possessing more advanced equipment, including domestically produced drones. Yet a conflict between the two countries would be unlikely to remain bilateral: alliances and competing regional interests could draw additional states and armed groups into the fighting.
An Ethiopian incursion into Eritrea could prompt a response from Egypt, Ethiopia’s longstanding rival in the dispute over Nile waters. Tensions between the two countries have centred on Ethiopia’s Grand Ethiopian Renaissance Dam (GERD), which Egypt fears will threaten its water security. The conflict could also affect Sudan, where one of the parties to the devastating civil war—the Sudanese Armed Forces—has been alleged to have links with the TPLF. Such claims, and the precise nature of any support, require careful verification.
On the other side, Ethiopia could potentially find support among Sudan’s Rapid Support Forces (RSF), whose relationship with the United Arab Emirates has drawn international scrutiny. Israel, which has historical ties with Ethiopia, could also figure in the wider strategic calculations, although its involvement should not be assumed.
Somalia, too, could be drawn into the crisis if Abiy pursues access to the Somaliland port of Berbera as an alternative to Eritrean ports. Ethiopia signed a memorandum of understanding with Somaliland, a self-governing territory whose independence is not internationally recognised, in a move that Somalia’s federal government in Mogadishu considers illegal. Any attempt to secure maritime access through coercion or territorial claims could further inflame relations in the Horn of Africa.
The consequences could extend across the Red Sea to Saudi Arabia and beyond. The Bab al-Mandab Strait, a critical global shipping chokepoint, is already under pressure from attacks on maritime traffic by Ansar Allah. A new war in the Horn of Africa could intensify insecurity along one of the world’s most strategically important trade routes, with potentially severe consequences for regional and global commerce.
The options for mediation are limited. The African Union remains a potential interlocutor, but the Intergovernmental Authority on Development (IGAD) has lost some of its credibility as a mediator following Eritrea’s withdrawal from the organisation, which Asmara attributed to perceived pro-Ethiopian bias. That leaves relatively few institutions capable of negotiating a way out of a conflict that could prove profoundly destabilising.
Turkey has previously sought to play a mediating role and retains historical ties that could provide a basis for engagement. The United States, under President Donald Trump, may be constrained by an increasingly transactional approach to diplomacy, while the European Union faces competing pressures closer to home. Neither constraint, however, should preclude efforts to prevent a regional war.
The cost of inaction could be far greater. Renewed fighting would mean further destruction, additional pressure on already fragile public health systems, severe logistical disruptions and significant damage to national and regional economies, with possible repercussions for global trade. Above all, the human cost could be immense, setting back development across the Horn of Africa for years.
The window for diplomacy may be narrow. Ethiopia is also reportedly considering constitutional changes that would merge the largely ceremonial presidency with the executive powers of the prime minister, creating an executive presidency. If enacted, such a change could further consolidate Abiy’s power and strengthen his ability to pursue policies with profound implications for Ethiopia and its neighbours.
The question is whether regional and international actors can act before political confrontation becomes military escalation. Preventing another Ethiopia–Eritrea war will require more than urgent statements of concern. It will demand credible mediation, renewed diplomatic engagement and a willingness to address the territorial, political and security grievances that have brought the two countries to the brink.
