Ethiopia, Eritrea break ties: Does the conflict risk becoming regional war? 

Eritrea has cut off diplomatic relations with neighbouring Ethiopia, escalating a long-simmering conflict between the two states rooted in territorial disputes and mutual accusations of interference.

The move comes as fighting flares in northern Ethiopia between Ethiopian federal troops and an opposition alliance that Addis Ababa accuses Eritrea of backing.

The clashes are the most severe in Ethiopia since its 2020-2022 civil war that killed hundreds of thousands of people.

But this time, the ripple effects could go further, potentially fuelling broader unrest in a region already plagued by numerous interrelated conflicts, analysts warn.

Here’s what we know about the Ethiopia-Eritrea conflict, the latest fighting in northern Ethiopia and what it could mean for the region at large:

Why did Eritrea break off ties with Ethiopia?

Eritrea announced it was severing ties with Ethiopia on Thursday, after Addis Ababa announced it would close its embassy in Asmara and expel 10 Eritrean diplomats.

In a statement, Eritrea’s Ministry of Foreign Affairs said Ethiopia’s actions had left it with “no option but to reciprocate in kind and sever all diplomatic ties with Ethiopia”.

The Eritrean ministry accused Ethiopia of pursuing a years-long “agenda of incessant hostility”, including by infringing on its coastal areas and arming fighters opposed to Ethiopia’s government.

Ethiopia has likewise accused Eritrea of backing armed groups opposed to its government. Both sides have rejected the other’s accusations.

The diplomatic breakdown follows months of worsening relations, driven largely by disputes over landlocked Ethiopia’s push for access to the Red Sea and allegations that Eritrea is backing the rebel Tigray People’s Liberation Front (TPLF), which leads the Ethiopian Peoples’ Forces Alliance for Survival, a rebel alliance fighting for control of parts of northern Ethiopia.

Have Ethiopia’s ties with Egypt and Sudan been hit, too?

Yes. Ethiopia accuses Egypt and Sudan of joining Eritrea in backing Tigrayan rebel forces, worsening already strained ties with both countries.

Ethiopia has long been at odds with Egypt over the status of Ethiopia’s Grand Ethiopian Renaissance Dam (GERD) project, which Cairo views as a risk to its water security and share of the Nile.

Ethiopia and Egypt have also expelled diplomats. Cairo ordered an Ethiopian diplomat to leave the country on Thursday, after Addis Ababa earlier kicked out an Egyptian diplomat, Egyptian state-linked media reported.

Egyptian state-linked broadcaster Al-Qahera News quoted an Egyptian official as calling Ethiopia’s move to expel the Egyptian diplomat as “regrettable and unjustified” and saying that Cairo responded in line with “the principle of reciprocity”.

The latest conflict also has implications for Sudan, whose military-backed government accuses Ethiopia of backing rebel forces it is fighting in its own civil conflict. Ethiopia rejects those allegations.

“The conflicts in Ethiopia and Sudan have become more interconnected, with the Ethiopian government and Sudanese Armed Forces accusing each other of harbouring and equipping respective opposition forces from inside their own borders,” Ahmed Soliman, senior research fellow at the Chatham House think tank’s Africa programme, told Al Jazeera.  “Egypt has also been drawn into the escalation with its long-running enmity with Ethiopia over the Nile.”

What is happening in northern Ethiopia?

Tigrayan-led rebel forces have engaged in clashes with Ethiopian government-backed forces in the country’s north since last week. Fighting is concentrated in three regions: Tigray, Amhara and Afar.

Al Jazeera’s bureau chief in Ethiopia, Mohammed Taha Tawakel, reported that forces loyal to the federal government have made significant gains in the Tigray region, taking control of several towns and closing in on the regional capital, Mekelle.

Further east in Afar, a pro-government armed group claimed on Thursday to have recaptured the town of Erebti, which rebel forces had taken control of earlier in the week. The pro-government group thanked the Ethiopian military for its “magnificent air support” and said it would pursue further advances.

Despite the pro-government advances, Tawakel reported that rebel forces still maintain what he described as a “strong rear link with Eritrea” along the countries’ border.

He also reported growing fears that fighting could move into major urban centres of Tigray, such as Adwa, Axum, Shire and Mekelle. Some people have already begun fleeing to Amhara and Afar, he added.

Outside northern Ethiopia, the conflict appeared to spill into the capital, Addis Ababa, for the first time early on Thursday, as an explosion was reported at the Ministry of Defence.

AFP quoted a diplomatic source as saying small drones were the most probable cause of the blast.

While Ethiopia’s army has a much larger arsenal of drones, rebel forces have previously used them to target airbases and airports in various parts of the country, reported conflict monitor ACLED.

What are the roots of the Ethiopia-Eritrea dispute?

Ties between the neighbours have been historically fragile. In 1962, Ethiopia annexed Eritrea. An armed independence struggle, led by Eritrea’s current President Isaias Afwerki, secured independence in 1993. The countries fought another border war from 1998 to 2000.

When Ethiopian Prime Minister Abiy Ahmed came to power in 2018, he moved to end the tensions and normalise diplomatic relations with Eritrea. During Ethiopia’s last civil war in 2020-2022, Eritrea even backed Ethiopia’s government against the TPLF.

But Abiy’s ambitions to seek direct sea access for landlocked Ethiopia have contributed to recent tensions, say analysts. Abiy has repeated that Ethiopia has a right to sea access, words that officials in Asmara take as a declaration of territorial conflict with Eritrea.

Many analysts fear it could.

Laura Hammond, professor in development studies at SOAS University of London, told Al Jazeera this scenario is already under way.

“The risks that conflict will spread to other countries, or that neighbours in the region will be brought into the present conflict are already playing out in terms of Eritrea’s support for the TPLF and the Alliance for Survival,” said Hammond.

“There is a strong possibility that Eritrea will become more involved in the conflict on the ground inside Tigray if it continues much longer,” she continued. “There is also a risk that the conflict could inflame relations with and inside Sudan.”

Martin Plaut, an analyst specialising in the Horn of Africa, also said there was a “real danger” of the conflict spreading.

“The situation is extremely tense and it would only require a spark to ignite a conflagration that could engulf [Ethiopia and Eritrea], as well as neighbouring Sudan,” he told Al Jazeera.