Cairo, Sep 11 (IANS): Egypt has said that Ethiopia's filling of the Grand Ethiopian Renaissance Dam (GERD) reservoir on the Blue Nile river without a consensus with Egypt and Sudan, the two downstream countries, is a violation of the Declaration of Principles, a previously signed tripartite deal.

On Sunday, Ethiopia's Prime Minister Abiy Ahmed announced on social media X, formerly known as Twitter, the completion of the fourth and final filling of the GERD reservoir.

"This is a violation by Ethiopia of the Declaration of Principles signed by the three sides in 2015," the Egyptian Foreign Ministry said in a statement.

The Declaration of Principles stipulates that the three countries must agree on the rules for filling and operating the GERD before commencing the filling process, the ministry was quoted as saying by Xinhua news agency.

It added that taking such unilateral measures constitutes a disregard for the interests and rights of the downstream countries and their water security under the rules of international law.

"This move and its negative effects place a burden on the resumed negotiations, which have been set for four months to conclude," the ministry said.

On Aug. 28, the Egyptian Ministry of Water Resources and Irrigation announced that the latest round of negotiations on the GERD dispute concluded in Cairo with no "tangible results."

Ethiopia started filling the dam in 2020 despite the opposition of Egypt and Sudan, which eventually led to the suspension of relevant tripartite negotiations in 2021.

Ethiopia started to build the GERD in 2011 and expects the giant hydropower project to generate more than 6,000 megawatts of electricity, but Egypt and Sudan have been worried that it might reduce their proportion of Nile water.