Ethiopia has finished the third phase of filling the reservoir for its massive Blue Nile project, the government announced on Friday, a procedure that has irritated the country’s downstream neighbors Egypt and Sudan.

The Grand Ethiopian Renaissance Dam (GERD), a $4 billion hydroelectric project, is important to Addis Abeba’s economic development, but Egypt and Sudan see it as a significant danger to their key water supply.

Long-running diplomatic efforts to resolve the three nations’ issue have had little result.

With a capacity of more than 6,000 megawatts, Ethiopia sees the GERD as the centerpiece of its drive to become Africa’s largest power exporter.

“Prime Minister Abiy Ahmed announced the successful completion of the GERD’s third filling,” Ethiopia’s prime minister’s office stated on Twitter, adding that the country was striving to “secure the advantages of the lower basin nations.”

On Thursday, Abiy hosted a ceremony to formally turn on the dam’s second turbine, six months after the first went online. Abiy’s office released photos of him standing at a podium in front of a massive plume of water being poured from the dam’s face.