Egyptian Minister of Water Resources and Irrigation Mohamed Abdel Aty said late on Monday that he received an official letter from his Ethiopian counterpart about the resumption of the filling process.
In a statement, Abdel Aty said Egypt rejects this unilateral measure and warned it threatens regional security.
Ethiopia’s $4.8-billion Grand Ethiopian Renaissance Dam (GERD) has raised concerns in the two downstream countries, Egypt and Sudan. A decade of arduous talks involving the three countries has reached a deadlock.
Egypt and Sudan are seeking a legally binding deal that would guarantee appropriate flows of water and a legal mechanism for resolving disputes before the dam starts operating.
Abdel Aty also sent a letter with the latest updates to the United Nations Security Council, which is expected to discuss the issue on Thursday.
Last year, Ethiopia celebrated the first filling of the dam thanks to seasonal rainfall.
Egypt, the most populous Arab country, relies almost exclusively on the Nile for farming, industry and domestic water use.
Ethiopia says Egypt’s worries about the dam are baseless.