Addis Ababa reportedly threatened a military counteroffensive nearly a week before the latest accounts of Eritrean troops entering northern Ethiopia, raising fears of another war between the neighbours.

Eritrean forces reportedly crossed into Tigray from Zelambesa, advancing towards Adigrat on Tuesday, 6 October, and Idaga Hamus on Wednesday, 7 October. Multiple media outlets, including Reuters and BBC, have cited eyewitness accounts of the troop movements.

The Armed Conflict Location & Event Data Project (ACLED) says Ethiopian drones struck Eritrean troops travelling in vehicles near Guada.

According to academic Derese Getachew Kassa, Ethiopia’s earlier warning was delivered to diplomats from the five permanent members of the UN Security Council and key European and African governments. Addis Ababa demanded that Eritrean forces withdraw or face a counteroffensive.

Ethiopian officials also accused Eritrea of embedding officers within the Tigray Defence Forces (TDF), supplying intelligence and logistical support, and deploying troops and mechanised units around Adwa, Adigrat and Shire.

Four scenarios on how conflict will unfold

Kjetil Tronvoll, a Horn of Africa specialist and professor of peace and conflict studies at Oslo New University College, has outlined four possible scenarios, ranging from a prolonged conflict to the overthrow of either government.

One is a war of attrition in which neither side secures a decisive victory, eventually forcing both governments to negotiate. Such a settlement could merely restore the hostility that defined their relationship before the 2018 peace agreement.

Another possibility, Tronvoll said, is that Eritrean President Isaias Afwerki, fearing military defeat, strikes a deal with Ethiopian Prime Minister Abiy Ahmed, handing over senior Tigray People’s Liberation Front (TPLF) leaders in exchange for guarantees of Eritrea’s sovereignty.

More dramatically, he raised the prospect of an Ethiopian military victory bringing down Isaias, who has ruled Eritrea since independence in 1993. That could open the door to political change in Asmara and negotiations over Ethiopian access to the sea.

The reverse scenario would see Eritrea and the Ethiopian Peoples’ Forces Alliance for Survival, a coalition of seven Ethiopian armed opposition movements, including the TPLF, potentially supported by Egypt and Sudan, gaining enough ground to overthrow Abiy. Tronvoll warned such a victory could plunge Ethiopia into further instability, with opposition factions turning against one another in a power struggle.

Does Eritrea have the military strength to take on Ethiopia?

Cameron Hudson, an independent political analyst specialising in the Horn of Africa and former director for African affairs at the US National Security Council under George W. Bush, questions whether Asmara can sustain another major war.

“What I struggle to understand is why Eritrea would move into Ethiopia,” he says. Eritrea maintains a large conscript army, but Hudson says reports from Asmara suggest soldiers suffer from poor nutrition and shortages of basic supplies.

“Given the state of the economy, you have to question how well armed they are and whether they have the latest generation weaponry,” he says.

By contrast, Hudson estimates Ethiopia has doubled, possibly tripled, the size of its army since the previous Tigray war, while receiving substantial weapons supplies from the United Arab Emirates. He believes this helps explain how federal forces recaptured Mekelle, the Tigrayan capital, so quickly following the latest rebel offensive.

“While Russia has traditionally been Eritrea’s closest and most reliable weapons supplier, in recent years Asmara has been rumoured to have acquired Mohajer drones from Iran, though the quantity of those remains unknown,” Hudson tells The Africa Report.

Can another all-out war be avoided?

“Sadly, my warnings of a new Eritrea-Ethiopia war in the making over the past three years have become a reality,” Tronvoll wrote on X.

Both governments are trading accusations of aggression, with little indication that either is prepared to back down. “Unless there is a dramatic reversal by some major diplomatic intervention to halt this conflict, it looks like the writing of another Ethio-Eritrean war is on the wall,” says Kassa.

Mekelle is a mere stop-over, our ultimate destination is Assab

The stakes extend beyond the two neighbours. Addis Ababa has accused Eritrea, Egypt and Sudan of backing its armed opponents, allegations all three governments deny.

On Sunday, 4 October, Egypt, Eritrea, Sudan and Somalia issued a joint declaration on Red Sea security, sovereignty and Nile water rights, strengthening their diplomatic alignment amid Ethiopia’s renewed domestic conflict.

Eritrea, meanwhile, accuses Abiy’s government of preparing to invade its territory under the pretext of self-defence. In a statement on X, Information Minister Yemane G. Meskel accused Ethiopian leaders of threatening to seize access to the Red Sea. He cited remarks attributed to an Ethiopian general who allegedly declared: “Mekelle is a mere stop-over, our ultimate destination is Assab.”

Yemane said Addis Ababa was fabricating allegations against Eritrea to justify a war of aggression. The general’s alleged remarks have not been independently verified.

For Abiy, fighting Eritrea would mean opening another front while his army battles armed opposition groups at home. For Isaias, taking on a larger, better-equipped neighbour could put his decades-long rule at risk.

Analysts warn that an Ethiopian advance towards Assab, further Eritrean incursions into Tigray or cross-border drone strikes could turn the confrontation into a much wider war.

Why has Eritrea entered the fight?

Four years ago, Abiy and Isaias were allies, fighting a common enemy in Tigray. Today, their armies are reportedly confronting each other in the same region.

Eritrea joined Ethiopian federal forces in 2020 against the TPLF, Ethiopia’s former ruling party. But the Pretoria peace agreement of November 2022 left the movement intact, frustrating Asmara’s ambition to crush an adversary dating back to the 1998-2000 border war.

Relations soured further as Abiy stepped up demands for access to the Red Sea.

Jalale Getachew Birru, ACLED’s East Africa analyst, says Eritrea’s suspected support for the Alliance for Survival, also called Tsimdo, reflects its opposition to Ethiopia’s maritime ambitions.

“Eritrea opposes Ethiopia’s quest to access the Red Sea through the port of Assab and seeks to create a buffer between Ethiopia and Eritrea [via] Tigray.” She adds that Eritrea’s intervention is intended to keep Ethiopian forces away from its border and prevent the fighting from spilling into Eritrea.