Ethiopia has accused Eritrea of joining forces with a hardline opposition faction in preparing to launch a war, according to a letter from the foreign affairs ministry obtained by AFP on Wednesday.
The Tigray People's Liberation Front (TPLF), which dominated Ethiopian politics for some 30 years, has been banned from political activity.
Relations have been extremely strained for several months between the two neighbors, more than 30 years after Eritrea gained independence from Ethiopia after a decades-long armed struggle.
Ethiopia's foreign minister wrote in the letter to UN Secretary General Antonio Guterres that "the collusion between the Eritrean government and the TPLF has become more evident over the past few months...".
"The hardliner faction of the TPLF and the Eritrean government are actively preparing to wage war against Ethiopia," it added.
The government in Addis Ababa also accuses its counterpart in Asmara and the TPLF of "funding, mobilizing and directing armed groups" in the Amhara region, where the federal army has been facing rebels for several years.
Eritrea's Information Minister Yemane Ghebremeskel and the TPLF have so far not responded to AFP's requests for comment on the accusations.
After independence in 1993, a bloody border war erupted between the two Horn of Africa countries from 1998 to 2000, leaving tens of thousands dead.
Relations thawed in 2018 after Ethiopian Prime Minister Abiy Ahmed came to power and signed a peace deal with President Isaias Afwerki, who has ruled Eritrea with an iron fist since independence.
The peace agreement earned Abiy a Nobel Peace Prize in 2019.
Eritrean troops backed Ethiopian federal forces during the bloody war in the northern Tigray region between 2020 and 2022, which left an estimated 600,000 people dead, according to the African Union.
- Sea access dispute -
Since the conflict ended, relations have again turned frosty, with Asmara accusing its landlocked neighbor of eyeing the Assab port on the Red Sea in southeastern Eritrea.
Abiy has repeatedly reiterated his desire for Ethiopia to regain sea access, lost legally after Eritrea's independence.
Ethiopian foreign minister Gedion Timothewos in the letter said Addis Ababa wants "to engage in good faith negotiations with the government of Eritrea".
He accused Asmara of trying "to justify its sinister machinations against Ethiopia by claiming that it feels threatened by Ethiopia's quest to gain access to the sea".
In June, a report by a US monitoring group accused Eritrea of rebuilding its army and destabilizing its neighbors.
Ghebremeskel, Eritrea's information minister, criticized the report by the NGO The Sentry and blamed "the new tension in the region" on Ethiopia.
Eritrea, one of Africa’s least populated countries with about 3.5 million people, has in recent months strengthened ties with Egypt, which also has strained relations with Ethiopia.
