The United Nations Security Council plans to meet Monday to discuss Egypt and Sudan's objections to Ethiopia's construction of a mega-dam on the Nile River, diplomatic sources said Thursday.

Egypt sees the structure as an "existential" threat and Sudan on Thursday warned of "great risk" to millions of human lives if the dam plan moves forward.

"We urge Egypt, we urge Ethiopia and Sudan to work together to intensify efforts to peacefully resolve outstanding differences," UN spokesman Stephane Dujarric said then.

Ethiopia says the dam is essential to its development, while Sudan and Egypt fear it could restrict their citizens' water access.

Ethiopia's progress would "compromise the safety of Sudan's Roseires Dam and thus subject millions of people living downstream to great risk", Sudan's Water Ministry said in a statement on Thursday.