Ethiopian Prime Minister Abiy Ahmed on Wednesday lauded the “historic” early filling of a massive dam on the Blue Nile River that has stoked tensions with downstream neighbours Egypt and Sudan.

“The completion of the first round of filling is a historic moment that showcases Ethiopians’ commitment to the renaissance of our country,” Abiy, the 2019 Nobel Peace laureate, said in a statement read on state television.

“The fact that we reached this milestone by our own efforts when no one else believed in our capabilities to accomplish such initiatives makes the moment even more historic,” he added.

The Grand Ethiopian Renaissance Dam (GERD) has been a source of tension in the Nile River basin ever since Ethiopia broke ground on it in 2011.

Egypt and Sudan view the dam as a threat to vital water supplies, while Ethiopia considers it crucial for its electrification and development.

“We conducted the filling of the dam without causing harm to anyone,” said Abiy.

Addis Ababa had long said it planned to begin filling the dam’s reservoir this month, in the middle of its rainy season, drawing objections from Cairo and Khartoum who wanted to first reach a trilateral agreement on how the dam would be operated.

Ethiopia’s announcement that it had hit its first-year target for filling the dam came Tuesday as the three countries were participating in talks overseen by the African Union to try to resolve the dispute.

After the call, leaders from the three countries said they had agreed to continue with the negotiations, though it was unclear what concrete progress had been made.

In a statement Wednesday morning, Egypt’s foreign ministry stressed “the necessity of reaching a binding legal agreement on the rules for filling and operating the Renaissance Dam” that would “include a legally binding instrument to resolve conflicts”.

But Ethiopia has resisted a legally binding dispute resolution process.

Ethiopian officials said the dam will not harm downstream countries.

They have also said this year’s filling was a natural and inevitable part of construction.

By filling the reservoir with 4.9 billion cubic metres (173 billion cubic feet) of water, Ethiopia is now in a position to test its first two turbines — an important step on the way toward actually producing energy.

Abiy noted Wednesday that Ethiopia wanted the dam to be fully operational by early 2023.