The U.N. Security Council on Wednesday urged Egypt, Ethiopia, and Sudan to resume African Union-led talks to reach a binding deal “within a reasonable timeframe” over the operation of a giant hydropower dam on the Blue Nile in Ethiopia.

Egypt and Sudan had both called on the council to help resolve the dispute after Ethiopia began filling the reservoir behind its Grand Ethiopian Renaissance Dam (GERD) in July for a second year. Ethiopia is opposed to any council involvement.

In a formal statement, agreed by consensus, the 15-member Security Council called “upon the three countries to take forward the AU-led negotiation process in a constructive and cooperative manner.”

“The Security Council encourages Egypt, Ethiopia, and Sudan to resume negotiations at the invitation of the Chairperson of the African Union (AU) to finalize expeditiously the text of the mutually acceptable and binding agreement on the filling and operation of the GERD, within a reasonable time frame,” the statement said.

The dam was the subject of a Security Council meeting in early July, even though its members have differing opinions on the need for the body dedicated to world peace to take on a subject related to the water supply.

Ethiopia had criticized any involvement of the Security Council, contending that the African Union was better positioned to help resolve the conflict.

The GERD, set to be Africa’s largest hydroelectric project when completed, has sparked an almost decade-long diplomatic stand-off between Addis Ababa and downstream nations Egypt and Sudan.

In July Ethiopia announced that the GERD was ready to produce electricity after completing the second phase of filling.

Ethiopia says the project is essential to its development, but Cairo and Khartoum fear it could restrict their citizens’ water access.