High on wins in Tigray, Ethiopia now has Eritrea in its crosshairs

On Friday, Ethiopian Foreign Minister Gedion Timothewos wrote to the U.N. Security Council, citing Article 51 of the U.N. Charter, to say Eritrean troops had advanced up to 38 miles into Ethiopia’s northern Tigray region and that Ethiopia would defend itself against the incursion.

On Saturday, Eritrean Foreign Minister Osman Saleh wrote a separate letter to the Security Council, calling Ethiopia’s accusations a “declaration of war.” Saleh cited a statement he attributed to Ethiopia’s deputy chief of staff, Gen. Abebaw Tadesse, who, according to the letter, said on September 27 that the “ultimate objective of the war [in Tigray] was to invade Assab,” a city on Eritrea’s Red Sea coast.

Ethiopian forces, meanwhile, reportedly struck Eritrean forces near Adirgat, in Ethiopia's Tigray region, with drones on Wednesday and Thursday. An unnamed security source told AFP that between 5,000 and 8,000 Eritrean troops are deployed in Tigray.

To understand why Ethiopian and Eritrean troops are now clashing, one must look back at 2020, when Ethiopia’s federal government under Prime Minister Abiy Ahmed fought the Tigray People’s Liberation Front (TPLF).

The TPLF dominated Ethiopia for nearly three decades before Abiy came to power in 2018, after which it retreated to its stronghold in the Tigray region, where it escalated tensions by refusing to join Abiy’s new ruling party, defiantly holding regional elections, and according to Abiy, attacking a federal army base. Eritrea fought alongside Ethiopian forces in the first Tigray war, which ended in 2022 with the Pretoria agreement, a ceasefire that left the hardest questions unresolved: disarmament, disputed territory and the withdrawal of non-federal forces. Eritrea was not party to the deal.

Since then, the trust that existed briefly between the two neighbors has withered. Ethiopia lost access to the sea when Eritrea became independent in 1993, and Abiy has spoken of the loss of the Eritrean port of Assab as a mistake “that will be corrected tomorrow.” Ethiopian officials often clarify that they seek access through peace and dialogue. But Eritrea feels its bigger neighbor intends to use force, as it highlighted in its recent letter to the United Nations.

As tensions between Asmara and Addis Ababa rise, Ethiopia is struggling to contain an internal rebellion that took shape on September 20, when the TPLF and six other armed groups announced the Ethiopian Peoples’ Alliance for Survival, with the stated aim of removing Abiy and installing a transitional government. Its members include the Amhara region’s Fano militias and the Oromo Liberation army, the groups behind the insurgencies in Ethiopia’s two largest and most populous regions.

Addis Ababa says Eritrea finances and directs the rebels. Asmara says Ethiopia has been planning to invade it for three years. The public evidence supports both accounts.

Because of its suspicions toward Ethiopia, Eritrea has started to open channels and coordinate with the TPLF, a surprising move given that this is the same movement it fought in the first Tigray war and, before that, during a devastating border war in 1998-2000, when the TPLF still dominated Ethiopian politics. A small state facing a much larger one needs a buffer, and Eritrea is trying to ensure the TPLF fills that role. As long as the TPLF remains armed, Ethiopia’s army cannot cleanly deploy to the border with Eritrea.

Eritrea also cultivated Egypt and Sudan’s army as allies. They have their own grievances with Ethiopia over its construction of the Grand Ethiopian Renaissance Dam and its alleged support for the Rapid Support Forces fighting Sudan’s military.

For Addis Ababa, these moves look like encirclement. An armed and hostile TPLF, an Eritrean patron and Egyptian and Sudanese alignment pose a clear danger—one that Abiy, however, recently brushed aside, claiming his government doesn’t have “an iota of fear” regarding the threat they pose.

Moreover, the Eritrean presence on Ethiopian soil was never new. The Pretoria agreement and its follow-up Nairobi declaration tied disarmament of Tigrayan forces to the withdrawal of “foreign and non-ENDF [Ethiopian National Defense Force] forces.” Eritrean troops left the larger towns but remained in contested border pockets. When asked about it in 2023, Eritrea’s president, Isaias Afwerki, called the question “nonsense.”

The reported advance now is deepening that presence, and Addis Ababa has been handed a casus belli it lacked before: that Eritrean forces are deep inside Ethiopia, and Ethiopia must fight back to defend itself.

On the diplomatic side, the walls have closed in. Ethiopia and Eritrea severed relations on October 1. Ethiopia and Egypt expelled each other’s diplomats, and Ethiopia’s military chief of staff, Field Marshal Birhanu Jula, expressly pointed the finger at “Shaebia” — the widely used term that refers to Eritrea’s government — as well as “Sudan, Egypt, and powers beyond” for supporting the TPLF’s renewed military insurgency.

On October 4, Egypt hosted the leaders of Eritrea, Somalia and Sudan at El Alamein on Egypt’s Mediterranean coast, where they declared that Red Sea governance belongs to coastal states — a blatant swipe at landlocked Ethiopia. Reuters, citing Egyptian security officials, reported that the four nations agreed to coordinate military and intelligence efforts if the conflict spills over Ethiopia’s borders. In short, a full-on war between Asmara and Addis Ababa would not necessarily remain bilateral for very long.

The most worrying signal is that Ethiopia’s military advantage may make escalation with Eritrea more tempting, not less. Ethiopian government forces have momentum. Government-allied units recaptured Mekelle, the capital of the Tigray region, on October 4, and Ethiopian airlines resumed flights to the city on Sunday.

Getachew Reda, a former Tigray leader now advising Abiy, greeted supporters at the airport on Sunday and promised the people “visible change.” Buoyed by this victory, Addis Ababa may calculate that it can resolve its long-standing security dilemma with Eritrea and its lack of a coastline in one stroke, by taking the fight north.

Yet, there are also strong reasons for restraint. The TPLF may look subdued for now, but other members of the rebel alliance, such as the Fano in Amhara and the Oromo Liberation Army in Oromio, remain committed to the fight. It is also crucial to note that the TPLF merely withdrew from Mekelle; its command remains intact and has not collapsed.

Compounding these security threats is the fact that most of Ethiopia’s imports travel along a single highway to Djibouti. The TPLF’s recent push into the Afar region, where this corridor lies, proved just how exposed the critical highway is and how much leverage the rebels stand to gain against the federal government.

Consequently, marching north into Eritrea and attempting regime change, or annexation, with half the country in revolt would be a gamble of the highest order for Ethiopia.

The international community meanwhile is not absent, but is thus far unconvincing. The African Union (AU) is headquartered in Addis Ababa. The organization has long been accused of going soft on its landlord, and much of the blame for the unresolved issues of the Pretoria agreement can be attributed to the AU's lethargy and systemic inaction.

Washington is better placed to mediate, given that Ethiopia has long been regarded as America’s most important partner in the Horn of Africa, and Washington is now warming to Eritrea. Ambassador Ervin Massinga had also shuttled between Mekelle and Addis Ababa and engaged the TPLF, yet as the insurgency in Tigray accelerated he blamed the TPLF’s “poor decision to launch a large-scale offensive."

Whether the U.S. can still help between Ethiopia and Eritrea is an open question, and so far it looks unprepared for what may come. Days before fighting resumed, the U.S. let the sanctions regime tied to the last Tigray war lapse, removing Eritrean officials and entities from the list, and it had already eased restrictions on arms sales to Addis Ababa.

On September 30, with fighting under way, Boeing signed a $5 billion aircraft deal with Ethiopian Airlines. Washington likes the story Abiy tells, of an Addis Ababa that becomes Africa’s Dubai, a $12.5 billion airport at Bishoftu meant to be among the largest in the world, and a country keen to do business with Washington as it undergoes an ambitious economic transformation. But a state sliding into a civil war and a simultaneous interstate war with its northern neighbor could soon have little to buy or build.