Sudan on Monday said that negotiations over Ethiopia's massive and controversial dam construction on the Blue Nile have been postponed for a week.
Talks between Ethiopia, Egypt and Sudan were suspended last week after Addis Ababa insisted on linking them to renegotiating a deal on sharing the waters of the Blue Nile.
"A meeting at the level of ministers of the three countries took place on Monday, during which Sudan asked to postpone the next meeting for one week for internal consultations," Sudan's water ministry said.
Egypt and Sudan view the Grand Ethiopian Renaissance Dam (Gerd) as a threat to vital water supplies, while Ethiopia considers it crucial for its electrification and development.
South Africa, which holds the presidency of the African Union and is mediating negotiations, has urged the countries to "remain involved" in the talks.
The dam has been a source of tension in the Nile River basin ever since Ethiopia broke ground on it in 2011.
"It is important that the parties should display magnanimity and understanding of each other's interests so as to move the process forward," South African International Relations Minister Naledi Pandor said last week.
The warning from Johannesburg was issued after a meeting of tripartite technical and legal committees which are seeking an agreement on how the dam should be filled and operated.
Sudan's water and irrigation minister, Yasser Abbas accused Ethiopia of shifting its position.
Ethiopia, he said, now insisted that the deal on the dam be linked to the wider question of sharing the waters of the Blue Nile.
"This new Ethiopian position threatens the negotiations under the aegis of the African Union, and Sudan will not participate in negotiations which include the subject of sharing Blue Nile waters," he warned.
Egypt and Sudan invoke a "historic right" over the river guaranteed by treaties concluded in 1929 and 1959.
But Ethiopia uses a treaty signed in 2010 by six riverside countries and boycotted by Egypt and Sudan authorising irrigation projects and dams on the river.
Egypt's water ministry, for its part, said Ethiopia's draft proposal lacked substance and contravened guidelines set at an AU summit on July 21.
"Egypt and Sudan demanded meetings be suspended for internal consultations," it said.
