But for Ethiopia, the huge project, set to be the largest hydroelectric plant in Africa, is an integral part of its efforts to develop the country and get electricity to millions of households.
The dam is nearing its completion, with the reservoir filling with water since 2020, and has already started generating power.
Egypt, along with Sudan – through which the Nile also flows, have been raising concerns that their essential water supplies would be under threat, especially if there are successive years of drought.
Multiple diplomatic efforts to reach a binding deal have not succeeded.
The most recent efforts ended in December last year with both countries accusing the other of intransigence.
In its letter to the Security Council, Ethiopia said Egypt was “only interested in perpetuating its self-claimed monopoly” over the river.
In recent weeks, tensions across the Horn of Africa have grown, especially after a military pact was agreed between Egypt and Ethiopia’s eastern neighbour Somalia.
Relations between Mogadishu and Addis Ababa deteriorated after landlocked Ethiopia signed a deal in January with the self-declared Republic of Somaliland over access to the sea and possible use of the coastline for a naval base.
Somalia sees Somaliland as part of its territory and said the agreement was an act of aggression.
This weekend, Ethiopia’s Prime Minister Abiy Ahmed warned against attacks on his country, saying anyone from “afar and nearby” daring to invade the country would be repelled.
He did not specify which country he was talking about.