In a letter to the Security Council on Friday, Ethiopian Foreign Minister Gedion Timothewos said Eritrean troops had advanced as far as 60km (37 miles) into Tigray, describing the alleged incursion as "a blatant act of aggression that engages Ethiopia's inherent right to self-defence". The letter invoked Article 51 of the UN Charter, which recognises a country's right to self-defence, but did not specify what measures Ethiopia was taking.
Eritrea rejected the accusations. In his own letter on Saturday, Foreign Minister Osman Saleh urged the Council to condemn Ethiopia's "deplorable declaration of war" and take "deterrent measures", warning that an offensive would cause "huge devastation to the peoples of both countries and destabilise the whole region". Asmara described Ethiopia's claims as a pretext for an offensive.
The exchange comes as Ethiopian troops and allied armed groups advance across Tigray, where forces from Asmara have allegedly crossed the border to support rebels fighting government forces. The two neighbours were allies during Ethiopia's devastating 2020-2022 Tigray war, but have since been at loggerheads over the 2022 peace agreement that ended the civil conflict, and over Ethiopia's demand for access to the Red Sea. Landlocked Ethiopia argues that securing direct sea access is essential, while Eritrea fears Addis Ababa intends to seize the port of Assab. Prime Minister Abiy Ahmed reiterated on Monday that Ethiopia must have access to the Red Sea.
The neighbours fought a deadly border war from 1998 to 2000. Relations improved after Abiy came to power in 2018 but have soured in recent years. Hossamaldeen Ibrahim, an analyst at the Bloomsbury Intelligence and Security Institute, said both countries' narratives contain "verifiable elements" and that "the danger lies in the fact that each side now treats the other's narrative as existential". Professor Matthias Rompel of Justus-Liebig-University Giessen said both sides have legitimate security concerns, but their accusations need to be distinguished from independently verified facts.