Eritrea, Ethiopia and Tigray were once bound together by a common enemy: the military government of Mengistu Haile Mariam. The Eritrean People’s Liberation Front (EPLF) and the Tigray People’s Liberation Front (TPLF) fought alongside each other against the Derg and helped bring it down in 1991. Yet the alliance contained a fundamental contradiction: the EPLF was fighting to create an independent Eritrean state, while the TPLF ultimately became the dominant force in a new Ethiopian political order. After Eritrea became independent in 1993, yesterday’s battlefield partners became rival governments—and after the 1998–2000 Eritrea-Ethiopia war, deeply entrenched enemies.
That history explains much of the extraordinary violence of the 2020–22 Tigray War. When Prime Minister Abiy Ahmed’s federal government went to war with the TPLF-led Tigray authorities in November 2020, Eritrea intervened on Ethiopia’s side. The resulting conflict was therefore never simply an internal Ethiopian confrontation: Ethiopian federal forces, Eritrean forces and Amhara forces fought against Tigrayan forces in a war marked by massacres, mass displacement, sexual violence and other grave abuses. The November 2022 Pretoria agreement stopped the large-scale fighting, but it did not settle the territorial, political and security disputes that produced the war. By 2026, those unresolved questions had again become a source of serious instability in northern Ethiopia.
The alliance that defeated the Derg
The origins of the relationship lie in the armed struggle against Ethiopia’s Derg regime.
The EPLF was fighting for Eritrean independence. Its struggle had begun decades earlier, following Ethiopia’s incorporation of Eritrea and, ultimately, the 1962 annexation of Eritrea as an Ethiopian province.
The TPLF emerged later, in 1975, initially pursuing the liberation of Tigray. Its objectives and those of the EPLF were therefore not identical. But both movements faced the same powerful enemy: the Derg government in Addis Ababa.
The common enemy encouraged cooperation despite ideological and strategic differences.
Human Rights Watch’s historical account describes the two movements as having developed a close alliance as the TPLF expanded its influence inside Ethiopia. The TPLF subsequently helped establish the Ethiopian People’s Revolutionary Democratic Front (EPRDF), an alliance of several ethnically based movements.
Their military successes eventually became decisive.
In 1991, the Derg collapsed. EPRDF forces entered Addis Ababa, while the EPLF took control of Asmara.
The former allies had achieved what they wanted from the war against Mengistu—but they now faced a much harder question:
What should the political relationship between Eritrea and Ethiopia look like after victory?
Independence changed everything
Eritrea became independent in 1993 after a referendum.
The event transformed the strategic map of the Horn of Africa.
Before independence, Ethiopia had possessed direct access to the Red Sea through Eritrean territory. After independence, Ethiopia became landlocked.
At first, however, the political relationship between the new Eritrean government and the EPRDF-led Ethiopian government remained relatively cooperative.
That cooperation was fragile.
Questions over trade, currency, borders and sovereignty increasingly strained relations. The two governments also disagreed over parts of their newly internationalized border. By 1998, those disagreements had developed into open war.
The 1998–2000 Eritrea-Ethiopia war was a watershed.
It demonstrated that the former liberation movements could become conventional interstate enemies—and that the border between Eritrea and Tigray was not simply a line separating two governments. It ran through a region with deeply interconnected communities, histories and political networks.
The war ended with a ceasefire and the Algiers Agreement, but relations remained hostile for years. Eritrea’s government adopted an intensely security-focused posture, while Ethiopia continued to be dominated by the EPRDF and, within it, the TPLF.
The TPLF’s long dominance inside Ethiopia
The TPLF’s importance cannot be understood simply by looking at Tigray.
After 1991, the TPLF became the dominant force inside the EPRDF, the coalition that governed Ethiopia for almost three decades.
That gave Tigrayan political and military elites influence far beyond the region’s demographic size.
The arrangement was increasingly controversial.
Other Ethiopian political forces accused the EPRDF system of concentrating power and restricting political competition. Human Rights Watch notes that the TPLF led the former coalition that governed Ethiopia until Abiy Ahmed became prime minister in April 2018.
Abiy’s arrival changed the balance.
He reorganized the governing coalition into the Prosperity Party and sought to reduce the political dominance of the old EPRDF structure.
The TPLF refused to join the new party.
The resulting confrontation was not merely a personality dispute. It reflected competing visions of Ethiopia’s political order.
The federal government under Abiy increasingly emphasized a stronger national political identity.
The TPLF defended the federal system and its political autonomy in Tigray.
The disagreement became progressively more difficult to contain.
Why Eritrea and Abiy became partners
One of the most consequential developments after Abiy came to power was his reconciliation with Eritrean President Isaias Afwerki.
The two governments restored diplomatic relations in 2018 after two decades of hostility.
For Abiy, rapprochement with Eritrea removed a major external threat and opened the possibility of regional economic and security cooperation.
For Isaias, the new Ethiopian government was led by a politician who had no direct role in the old TPLF-dominated order.
That mattered enormously.
The TPLF and Eritrean leadership had once fought alongside each other, but the 1998–2000 war had transformed their relationship into one of profound hostility.
The 2018 Ethiopia-Eritrea peace agreement therefore produced an unusual political alignment:
The former TPLF-led Ethiopian establishment and Eritrea were no longer on the same side. Abiy’s government and Eritrea increasingly were.
Human Rights Watch described the 2018 agreement as ending two decades of intermittent conflict between Eritrea and Ethiopia.
The peace also produced a Nobel Peace Prize for Abiy in 2019.
But beneath the diplomatic breakthrough, the TPLF-Eritrea relationship remained unresolved.
The road to the Tigray War
By 2020, relations between Addis Ababa and Mekelle had deteriorated sharply.
The federal government postponed national elections, citing the COVID-19 pandemic. Tigray’s regional authorities rejected the postponement and proceeded with their own regional election.
Both sides increasingly questioned the other’s legitimacy.
Then came the decisive rupture.
On November 4, 2020, Abiy’s government announced that TPLF forces had attacked a federal military base in Tigray. The federal government launched military operations in response.
The TPLF disputed the government’s characterization of the events, but fighting rapidly expanded.
The federal government initially moved quickly.
Tigrayan forces were pushed back from major urban centers.
But the war did not end.
Instead, it became a prolonged and extraordinarily destructive conflict.
Why Eritrea entered the war
Eritrea’s intervention is one of the most important—and most controversial—features of the conflict.
Eritrean forces crossed into Tigray and fought alongside Ethiopian federal forces against Tigrayan forces.
This was not simply an accidental consequence of the fighting.
Eritrea and the TPLF had a long-standing strategic hostility dating back to the 1998–2000 war.
From Asmara’s perspective, the TPLF represented the political force that had dominated Ethiopia during the period of Eritrea’s prolonged confrontation with Addis Ababa.
The opportunity to weaken that adversary was therefore strategically significant.
For Abiy’s government, Eritrean military involvement provided an additional force against the TPLF at a moment when the federal government was fighting for control of the region.
The arrangement produced a remarkable reversal of the region’s earlier history.
The EPLF’s successor government was now fighting alongside the Ethiopian state against the TPLF—the movement with which the EPLF had once fought to overthrow the previous Ethiopian government.
What happened to civilians
The war was not only a military contest.
Human rights organizations documented extensive abuses by multiple parties.
Human Rights Watch documented Eritrean forces committing killings, sexual violence, pillage and other serious violations in Tigray. It also documented abuses by Ethiopian federal forces and allied forces.
The conflict also produced a humanitarian catastrophe.
Access to Tigray was heavily restricted during important phases of the war, complicating independent verification of events and limiting humanitarian assistance.
The scale of the conflict makes simple narratives particularly dangerous.
The Ethiopian federal government accused the TPLF of initiating the conflict through its attack on the military base.
Tigrayan authorities and supporters pointed to the federal government’s political and military campaign against their region.
Meanwhile, independent investigations documented serious abuses by forces on multiple sides.
These propositions can coexist.
Explaining how the war began does not excuse what happened afterward.
Eritrean forces and the Shire-Aksum-Humera axis
Eritrea’s involvement was particularly significant because Tigray borders Eritrea to the north.
That geography gave Eritrean forces direct access to the conflict.
Eritrean troops operated in several parts of Tigray and remained in some areas even after the November 2022 ceasefire.
Human Rights Watch documented allegations including extrajudicial executions, sexual violence, abductions and looting by Eritrean forces after the Pretoria agreement, while also reporting interference with humanitarian and African Union monitoring activities.
The issue became particularly important after the formal end of the war because the peace agreement was signed between the Ethiopian government and the TPLF—not Eritrea.
That created an immediate implementation problem.
How could an agreement between Addis Ababa and the TPLF fully resolve a conflict when Eritrean troops were still present on Ethiopian territory?
The Pretoria Agreement
In November 2022, the African Union-mediated peace process produced the Cessation of Hostilities Agreement, commonly known as the Pretoria Agreement.
The talks began in South Africa in October 2022.
On November 2, the Ethiopian government and TPLF signed the agreement.
The AU described it as a framework intended to end the fighting, restore humanitarian access, restore services and create conditions for peace, security and stability in Tigray.
The agreement represented a major diplomatic achievement.
It stopped the large-scale fighting between the federal government and Tigrayan forces.
It also provided for the disarmament of Tigrayan forces and a political process for addressing the region’s future.
But Pretoria did not solve every underlying dispute.
The agreement could stop a war without resolving the political questions that produced it.
That distinction is central to understanding why northern Ethiopia remained unstable.
The questions Pretoria left unresolved
Several issues became particularly difficult.
Western Tigray
Territory in western Tigray became one of the most consequential disputes.
During the war, Amhara forces and allied groups took control of areas claimed by Tigray.
Large numbers of Tigrayan civilians were displaced.
Human Rights Watch has described continuing abuses and the unresolved status of Western Tigray as major obstacles to lasting peace.
For displaced Tigrayans, returning home is not simply a humanitarian question.
It is also a question of who controls the territory.
Eritrean troops
The Pretoria framework addressed the withdrawal of non-federal forces, but implementation was uneven.
The Rift Valley Institute reported in 2026 that Eritrean forces largely withdrew from Tigray’s heartland after the agreement but remained entrenched in contested border areas.
That matters because the Eritrean presence is connected to a broader security calculation.
Eritrea does not view Tigrayan armed power solely as an internal Ethiopian political issue. Its own national-security calculations remain heavily influenced by its history with the TPLF.
Tigrayan disarmament
Pretoria required the disarmament of Tigrayan forces.
But disarmament is difficult when territorial disputes remain unresolved and when neighboring Eritrea and other Ethiopian regions remain perceived as security threats.
This created a classic post-conflict dilemma:
How do you persuade one side to surrender military capability before it believes the political settlement is secure?
Accountability
The war produced allegations of war crimes and crimes against humanity.
The Pretoria framework included commitments relating to transitional justice, accountability and reconciliation.
But implementation has been controversial.
Human Rights Watch has argued that Ethiopia’s subsequent transitional-justice process has not provided sufficient independent scrutiny of alleged grave abuses.
For survivors, therefore, peace and justice have not necessarily moved together.
Pretoria stopped the war—but did not erase the war’s causes
This is the most important distinction.
A cessation of hostilities is not the same thing as a political settlement.
Pretoria dramatically reduced battlefield violence.
It did not settle:
- The status of contested territories
- The return of displaced populations
- The political relationship between Tigray and Addis Ababa
- The long-term status of Tigrayan armed forces
- Eritrea’s security relationship with Tigray
- Accountability for wartime abuses
- The wider constitutional dispute over Ethiopia’s federal system
The Rift Valley Institute’s 2026 assessment concluded that the agreement ended two years of war but postponed rather than resolved many of its underlying causes.
That distinction became increasingly important after 2024.
Tigray’s internal political split
The postwar period also exposed divisions within Tigray itself.
The TPLF was not a perfectly unified political organization.
Disagreements developed over how Tigray should relate to the federal government, how Pretoria should be implemented and how the region should respond to unresolved territorial and security issues.
The Rift Valley Institute reported that competition between Tigray’s interim leadership and TPLF hardliners intensified after the war, eventually contributing to major leadership changes in 2025.
This matters because “Tigray” should not be treated as a single political actor.
There are TPLF officials, former TPLF officials, Tigray regional authorities, military commanders, civilian constituencies and displaced communities whose interests do not always coincide.
The same caution applies to “Ethiopia.”
The federal government, Amhara forces, Oromo political actors and other regional constituencies have different interests in the future of the country.
Why the northern crisis returned
By 2026, the peace had become increasingly fragile.
Human Rights Watch reported rising tensions between the federal government and TPLF, including disputes over territory, displaced people’s return and disarmament. Both sides accused the other of military mobilization.
In January 2026, Ethiopian federal forces and Tigrayan forces reportedly clashed again.
The underlying issues had not disappeared.
They had simply moved from a full-scale war into an unstable political and military standoff.
That is why the current crisis should not be described as simply “the Tigray War returning.”
The political landscape is different.
The military balance is different.
Eritrea’s relationship with Ethiopia is different.
And the TPLF itself has changed.
But the unresolved questions surrounding territory, security, federalism and regional power remain.
The remarkable reversal of the Eritrea-TPLF relationship
The historical irony is difficult to miss.
In the 1980s:
EPLF + TPLF → fight the Derg
In the 1990s:
EPLF/Eritrea + TPLF/Ethiopia → initially cooperate, then fight each other
In 2018:
Eritrea + Abiy’s Ethiopia → restore peace
In 2020–22:
Eritrea + Ethiopian federal and Amhara forces → fight Tigrayan forces
After Pretoria:
Ethiopia and Tigray attempt to implement peace while Eritrea remains a separate security actor
And by 2026:
Ethiopia, Eritrea and Tigray are again locked into a rapidly changing regional security crisis.
The lesson is that alliances in the Horn of Africa are rarely permanent.
They are shaped by security interests, territorial questions, political legitimacy and calculations about who represents the greatest threat at a particular moment.
Why Ethiopia and Eritrea can become enemies again
The 2018 peace did not eliminate the strategic contradictions between the two states.
One important source of renewed tension is Ethiopia’s desire for reliable access to the Red Sea.
Ethiopia has been landlocked since Eritrea’s independence and has increasingly argued that its economic size and geographic position require dependable maritime access.
Eritrea, however, views its coastline as a central component of its sovereignty and national security.
That makes maritime access more than an economic question.
It intersects with the old security relationship between the two governments.
If Ethiopia believes Eritrea is obstructing its economic future, pressure may increase.
If Eritrea believes Ethiopia is seeking military or sovereign control of a Red Sea outlet, Eritrean threat perceptions may increase.
And if Tigray again becomes militarily active, the geographic proximity of Eritrea makes it difficult for Asmara to remain a detached observer.
The result is a potentially dangerous triangle.
The 2026 crisis is not simply a replay of 2020
The current situation contains important differences from the original Tigray War.
The TPLF is no longer the dominant force it was before 2020.
Tigray’s political establishment is divided.
The federal government has learned from the previous war.
Eritrea and Ethiopia have moved from the 2018 peace partnership back toward open hostility.
And the regional environment is more complicated, with Sudan’s war, Red Sea competition and Ethiopia’s maritime ambitions overlapping with the Tigray question.
Recent reporting in October 2026 indicates that fighting has again erupted in northern Ethiopia, with airstrikes and artillery reported in Tigray. Reuters reported that Ethiopia has accused Eritrea, Sudan and Egypt of supporting opposing forces, allegations those governments deny.
That does not mean a new regional war is inevitable.
But it demonstrates how quickly a domestic Ethiopian conflict can acquire international dimensions.
What would a durable settlement require?
A durable peace in northern Ethiopia requires more than keeping troops away from the battlefield.
At minimum, the parties would need to address four interconnected questions.
First, territory. Western Tigray and other contested areas require a credible political process that addresses both territorial claims and the rights of displaced populations.
Second, security. Tigray cannot be expected to feel secure while fearing armed intervention, while Addis Ababa cannot accept a powerful regional armed force outside effective federal control indefinitely.
Third, Eritrea. A settlement inside Ethiopia will remain vulnerable if Ethiopia-Eritrea relations continue to deteriorate. Eritrea’s security concerns about Tigrayan forces and Ethiopia’s concerns about Eritrean military involvement have to be addressed separately from the internal constitutional dispute.
Fourth, accountability. A peace that leaves victims without credible avenues for truth and justice may stop fighting without producing reconciliation.
These problems are difficult precisely because solving one can complicate another.
Disarming Tigrayan forces without resolving territorial disputes can increase Tigray’s insecurity.
Returning displaced people without resolving territorial administration can reignite local conflict.
Pursuing accountability without political guarantees can cause former combatants to resist the peace process.
And ignoring Eritrea can leave an armed regional power outside the central settlement.
The unresolved northern Ethiopian crisis
The deepest lesson from the EPLF-TPLF story is that today’s alliance can become tomorrow’s strategic threat when the underlying interests change.
The EPLF and TPLF were once indispensable partners because both needed to defeat the Derg.
After 1991, their interests diverged.
Eritrea wanted an independent state protected from Ethiopian domination.
The TPLF became the dominant force in an Ethiopian government that controlled the territory surrounding Eritrea.
The 1998–2000 war transformed political rivalry into generational hostility.
Abiy’s rise temporarily rearranged the equation, bringing Ethiopia and Eritrea together against the TPLF.
The 2020–22 war then produced one of the most devastating conflicts in modern Ethiopian history, with Eritrean troops fighting inside Tigray and extensive abuses documented by rights organizations.
Pretoria stopped the large-scale war.
It did not resolve the fundamental questions of who controls disputed territory, how Tigray is secured, what role the TPLF should play in Ethiopia, how Eritrea relates to its former adversary, and how Ethiopia’s federal system should distribute political power.
Those questions are why the northern Ethiopian crisis remains unfinished.
And they are why understanding the history of the EPLF and TPLF is essential to understanding the present: the conflict is not simply an ancient ethnic rivalry or a dispute between neighboring governments. It is the accumulated consequence of liberation movements becoming states, former allies becoming rulers, borders becoming international frontiers, and wartime security calculations surviving long after the original war has ended.