On Sunday, Ethiopian prime minister Abiy Ahmed (pictured above) announced that the fourth and final filling of the Grand Ethiopian Renaissance Dam (GERD) was complete in a move that was immediately denounced by Egypt as a violation of international law.

The two countries have been engaged in a long-running dispute over the dam, which Ethiopia says is vital for its power needs but Egypt fears could limit its access to Nile waters. The Nile contributes 90% of Egypt’s fresh water and underpins its irrigation and power generation.

The latest friction comes despite hopes of a diplomatic breakthrough sparked in July when Abiy Ahmed and Egypt’s President Abdel Fattah al-Sisi said they planned to resume negotiations over the dam and complete them within four months.