A dispute between Egypt and Ethiopia over an upstream Nile dam has escalated into a heated war of words over the hydropower barrage.

Ethiopia is building a $4 billion dam on the Blue Nile, a tributary of the Nile River, near the border with Sudan, saying the project is necessary to provide the country with much needed-electricity.

Egypt fears that the dam could stem the flow of the Nile, on which it depends for around 90 percent of its water supply.

Read more: Nile dam spurs fears of Egypt-Ethiopia 'water war'