NAIROBI, Kenya (AP) — Ethiopia told the U.N. Security Council on Friday it is taking measures in self-defense against Eritrea, accusing its neighbor of sending troops across the border and occupying parts of northern Ethiopia.
The declaration adds to fears of a wider conflict as government-allied forces report advances in Tigray, a region devastated by a previous war.
In a letter dated Friday, Foreign Minister Gedion Timothewos invoked Ethiopia’s right to self-defense under Article 51 of the U.N. Charter. He did not specify what measures the country was taking.
The letter, obtained by The Associated Press, accused Eritrea of deploying infantry and mechanized units in recent weeks and supporting, financing, arming and directing insurgent groups. It did not identify the occupied areas or provide evidence supporting its allegations.
Ethiopia had repeatedly urged Eritrea to withdraw its forces, Gedion wrote. The AP could not independently verify the allegations.
Eritrean Information Minister Yemane Gebremeskel accused Ethiopia on Friday of pursuing aggression against Eritrea through its demands for sovereign access to the Red Sea. Writing on X, he did not explicitly confirm or deny the reported troop crossings.
Eritrea announced last week it was severing diplomatic ties after Ethiopia expelled 10 Eritrean diplomats and closed its embassy in Asmara.
Ethiopian Prime Minister Abiy Ahmed reiterated Monday that Ethiopia must have access to the Red Sea. Ethiopia’s Foreign Ministry said it remained committed to dialogue with its neighbors.
The accusations deepen a rift between countries whose armies fought together against the Tigray People’s Liberation Front from 2020 to 2022.
Researchers at Ghent University in Belgium estimated the previous war caused about 500,000 civilian deaths in Tigray from violence, famine and the collapse of health services.
Government and allied forces took Idaga Hamus early Friday and Abiy-Adi, in the Tembien area, on Thursday afternoon, according to Ermiyas Ababu, a commander of the government-allied Tigray Peace Force.
Residents also reported the takeover of Idaga Hamus. Gebremedhin Kihishen, a business owner in Tembien, said government-allied forces controlled Abiy-Adi.
It was unclear from those accounts who held the towns immediately before the reported government advance or whether Eritrean troops were involved in the fighting.
Ermiyas previously reported Eritrean personnel entering Adigrat on Tuesday and Idaga Hamus on Wednesday, citing reports from his personnel.
The Armed Conflict Location & Event Data monitoring group, known as ACLED, separately said Eritrean troops crossed at Zelambesa on Wednesday and came under drone attack while traveling toward Idaga Hamus. It attributed the strikes to Ethiopia’s military. The AP could not independently verify either account.
The TPLF joined six other opposition groups last month in an alliance seeking to oust Abiy. Fighting escalated late in September, undermining the 2022 peace agreement, and rebels seized Tigray's capital Mekelle and its airport.
The rebels announced their withdrawal Oct. 3 and government-allied fighters entered the city.
In Mekelle, federal police on Friday called over loudspeakers for residents to help establish a new administration. Government offices remained shut, and no administration had taken office by that morning. The Tigray Peace Force imposed an overnight curfew Wednesday.
The U.S. Embassy said Thursday that telecommunications had resumed in Mekelle and much of Tigray, while mobile banking and electricity had partially resumed. All remained subject to interruption.
During the previous war, the AP documented accounts accusing Eritrean soldiers of killings, rape and looting. Eritrean President Isaias Afwerki dismissed allegations of abuses by his forces as “a fantasy” in 2023.
Filmon Equar Hailu in Mekelle, Ethiopia, Amir Aman Kiyaro in Hamburg, Germany, and Farnoush Amiri at the United Nations contributed to this report.
Ethiopian Prime Minister Abiy Ahmed speaks during a session of the Ethiopian Parliament in Addis Ababa, Ethiopia, Monday, Oct. 5, 2026. (Ethiopian Prime Minster's Office via AP)
In this photo taken with a smartphone, Ethiopian federal police officers gather on a road in Mekelle, Tigray Region, Ethiopia, Thursday, Oct. 8, 2026. (AP Photo/Filmon Equar Hailu)
