(Bloomberg) -- Egypt, Ethiopia and Sudan said they reached an agreement on the operation of a giant dam on a Nile tributary, a sign of easing tensions in the region.

The countries issued a joint statement along with the U.S. and World Bank, which had participated as observers at meetings in Washington this week. The pact lays out a plan to fill the reservoir in stages -- a process crucial to ensuring a reliable flow to Egypt, which depends on the Nile for almost all of its fresh water.

Treasury Secretary Steven Mnuchin intervened late last year in the long-running dispute over the Grand Ethiopian Renaissance Dam, known as GERD, which threatened freshwater supplies and had put two of Washington’s most prominent African allies at odds with each other. David Malpass, president of the World Bank, was also involved in the talks.

The deal “addresses the filling goals of Ethiopia and provides electricity generation and appropriate mitigation measures for Egypt and Sudan during prolonged periods of dry years, drought and prolonged drought,” the U.S. Treasury said in a statement released Wednesday after three days of negotiations.

The agreement for what is set to be Africa’s largest hydropower project will be finalized in Washington on Jan. 29, according to the statement.

To contact the reporter on this story: Saleha Mohsin in Washington at smohsin2@bloomberg.net

To contact the editors responsible for this story: Alex Wayne at awayne3@bloomberg.net, Joshua Gallu, Justin Blum

©2020 Bloomberg L.P.