Egypt said the move was “a violation of international laws and norms that regulate projects built on the shared basins of international rivers,” and had expressed its “firm rejection of this unilateral measure”, its irrigation ministry said in a statement late Monday.

The Grand Ethiopian Renaissance Dam, which is set to be Africa’s largest hydroelectric project when completed, is the source of an almost decade-long diplomatic stand-off between Addis Ababa and downstream nations Egypt and Sudan.

Ethiopia says the project is essential to its development, but Cairo and Khartoum fear it could restrict their citizens’ water access.
Both countries have been pushing Addis Ababa to ink a binding deal over the filling and operation of the dam.

‘Existential threat’

The Nile — which at some 3,700 miles (6,000 kilometres) is one of the longest rivers in the world — is an essential source of water and electricity for dozens of countries in East Africa.

Egypt, which depends on the Nile for about 97 percent of its irrigation and drinking water, sees the dam as an existential threat.

Sudan hopes the project will regulate annual flooding but fears its dams would be harmed without agreement on the Ethiopian operation.

The 145-metre (475-foot) mega-dam, on which construction began in 2011, has a capacity of 74 billion cubic metres.