When Ethiopian prime minister Hailemariam Desalegn visits Egypt this week to discuss bilateral cooperation in sectors like health, education, and agriculture, one contentious issue will stand out: the completion of Africa’s largest dam.

It’s no secret what Egypt thinks about the Grand Ethiopian Renaissance Dam (GERD), the centerpiece of the Horn of Africa nation’s bid to become Africa’s biggest exporter of electricity. From the get-go, Egypt was opposed to the idea of the dam, and politicians including former president Mohamed Morsi were caught on air proposing military action against Ethiopia.

Located in the headwaters of the Blue Nile and planned to produce 6,000 megawatts of electricity, the dam will be Africa’s largest hydroelectric power plant and will boost the economic growth of Ethiopia. As a downstream, desert nation, Egypt says the dam will disrupt the flow of the Nile to its almost 100 million people, potentially crippling its agricultural sector and industries.

During the filling of the reservoir, experts say the Nile’s freshwater flow to Egypt may be cut by 25%. This will also compound the other problems threatening the Nile including climate change, population boom, urban sprawl, besides rising sea levels that lead to saltwater intrusion.

Based on international accords signed in 1929 and amended in 1959, Egypt has always asserted its right to the lion’s share of the Nile’s water. But under president Abdel Fattah el-Sisi, and as the dam has continued to take shape, Cairo seemed to have softened its stance, even signing a cooperation agreement in 2015 to study the potential impact of the dam. But those talks are yet to bear any fruit, and to boost its position in the dispute, Sisi launched a charm offensive by visiting upstream Nile Basin nations including Sudan, Tanzania, Rwanda—and even Ethiopia.

And now, geopolitical strains between Sudan and Egypt are threatening to undermine any progress and unravel a regional crisis. Tensions over who owns the Hala’ib Triangle on the Red Sea has flared again, leading Khartoum to recall its ambassador from Cairo in early January. In retaliation, Egypt sent hundreds of its troops to a United Arab Emirates military base in Eritrea, and Sudan responded by closing its border with Eritrea and sending more troops there.

Reuters/Tiksa Negeri/Files Ethiopia’s Grand Renaissance Dam.

The current tensions are also being exacerbated by what Cairo sees as Turkish meddling in the region. In December, president Recep Tayyip Erdogan of Turkey visited Sudan, with president Omar al-Bashir agreeing to temporarily hand over the Red Sea port city of Suakin to Turkey to increase tourism—a move Cairo saw as Turkey’s attempt to build it third base abroad after the ones in Qatar and Somalia. Cairo also accuses both Khartoum and Ankara of supporting the Muslim Brotherhood, the banned Islamist outfit that was once the country’s most powerful political group.

On the Nile issue, Egypt also believes al-Bashir is on Ethiopia’s side and recently proposed excluding Sudan from the negotiations. Issandr El Amrani, the North Africa project director for the International Crisis Group, says Sudan’s shift is in part because of what it stands to gain including electricity supply and the prevention of flooding during rainy seasons.

The spat over the Nile also takes on a new significance as Egypt heads to the polls in March. President Sisi has said Egypt doesn’t want a war with its neighbors and warned Egyptian media from using “offensive language” against them. But with no “trusted mechanism” for negotiations now, El Amrani says the dust-up will only intensify.

“The Nile issue is really important in Egypt,” he said. And “the larger question that we have to ask ourselves now is ‘Where is this headed?’”