The Grand Renaissance dam, under construction in northern Ethiopia, will become when completed Africa's largest hydroelectric power station.

But Egypt, which relies on the Nile for 80% of its water, is worried that the dam will greatly affect its already scarce water supply.

The latest round of talks, to be mediated by the US, follows tough positions taken by Egypt and Ethiopia that have seen previous meetings end without progress.

At the centre of the dispute are plans to fill up the mega dam, which will eventually have a 6,000 megawatt capacity, according to the Ethiopian government. This is the equivalent of at least six nuclear power plants.

Ethiopia wants to do it in six years, Egypt has proposed a 10-year period fearing the project will allow Ethiopia to control the River Nile’s flow.

Once completed, the $4bn (£3bn) dam will be the biggest on the continent as Ethiopia positions itself to become Africa's largest energy exporter.

But the construction has been affected by constant delays and it is not clear if it will be operational by the 2021 deadline set by the government.