Foreign ministers from Egypt, Ethiopia and Sudan kicked off negotiations in Kinshasa on Sunday over Addis Ababa's contestedGrand Ethiopian Renaissance Dam (GERD) on the Blue Nile, officials said.
The dispute over the giant dam, built across this treasured river, has been brewing for around a decade.
President of the Democratic Republic of Congo (DRC) Félix Tshisekedi -- who became chairman of the African Union in February, urged the foreign ministers "to launch a new dynamic".
For Tshisekedi, "The human dimension must be at the heart of these tripartite negotiations."
"I ask you all to make a fresh start, to open one or several windows of hope, to seize every opportunity," he said.
He welcomed the willingness of the participants "to seek African solutions for African problems together".
Egypt and Sudan this month called on Kinshasa to steer efforts to relaunch negotiations on the contested dam.
The people of all three countries have a right to water, food and health, he stressed.
The US ambassador to the DR Congo, Mike Hammer, attended the start of the talks, which were set to wrap up on Monday.
The Nile -- the world's longest river, is a lifeline supplying both water and electricity to the 10 countries it crosses.
Upstream Ethiopia says hydroelectric power produced by the GERD will be vital to meet the energy needs of its 110 million people.
Egypt, which depends on the Nile for about 97%of its irrigation and drinking water, sees the dam as an existential threat.
Sudan -- also downstream, fears its own dams will be compromised if Ethiopia proceeds with filling the GERD before a deal is reached.
Last Tuesday, Egyptian President Abdel Fattah al-Sisi stressed his country's concerns, warning, "Nobody will be permitted to take a single drop of Egypt's water, otherwise the region will fall into unimaginable instability."