Ethiopia has started filling the reservoir of the Grand Renaissance Dam built on the River Nile, Sileshi Bekele, Minister of Water, Irrigation and Energy, has told state broadcaster EBC.
Mr Sileshi confirmed latest satellite images showing water levels rising in the reservoir were indeed as the result of filling the dam.
The $5bn (£3.9bn) hydropower project is at the centre of a dispute between Ethiopia, Egypt and Sudan.
Talks to end the decade-old row ended on Monday with no agreement on key technical concerns raised by Egypt and Sudan.
The new satellite images taken between 27 June and 12 July show a steady increase in the amount of water being held back by the dam.