Egypt on Wednesday sent a letter to South Africa, the current chair of the African Union (AU), to express its rejection of a recent proposal by Addis Ababa on the filling of its mega hydropower dam on the Blue Nile, the Egyptian irrigation ministry said.

Egypt said this week that an Ethiopian draft proposal on the Grand Ethiopian Renaissance Dam (GERD), which was sent by the country’s water minister to his Egyptian and Sudanese counterparts, provides guiding rules of the dam’s filling, while lacking the guidelines regulating the project’s operation, any elements indicating a binding deal, and a legal mechanism to settle disputes.

Sudan, meanwhile, said the draft addresses only the first filling of the dam and says an agreement on the dam’s long-term operation is contingent on reaching a broader agreement on the Blue Nile waters, which it rejects.

In a statement on Wednesday, Egypt’s irrigation ministry said the letter sent to South Africa reaffirms Cairo’s rejection of Ethiopia’s “unilateral” initial filling of the GERD last month.

It said the Ethiopian proposal presented on Tuesday violates directives by AU in July which called on the three countries to swiftly finalise a legally binding agreement.

Addis Ababa announced last month it had completed the first-year filling of the dam’s reservoir due to the rainy season.

Sudan has also rejected the proposal in a letter sent to the Africa Union chair on Tuesday, saying that Ethiopia violated the Declaration of Principles signed between by the three countries in 2015.

In the letter, Khartoum said that it may not continue with the talks if Ethiopia insists on its position.

Ethiopia announced on Tuesday that it had presented to Egypt and Sudan a version of what it called guidelines and rules for the mega-dam, and that both countries had requested to adjourn the talks to consider the Ethiopian proposal.

Both Egypt and Sudan slammed the Ethiopian statement.