Egypt, Ethiopia and Sudan have once again failed to agree on a new negotiating approach to resolve a dispute over the dam that Addis Ababa is building on the Blue Nile River.
The talks on Wednesday were the first since US president Donald Trump's comments in which he said Cairo could end up 'blowing up the dam', prompting a strong protest from Ethiopia.
In July, Ethiopia began filling the dam's reservoir, angering Egypt which fears that its water supply could face severe disruption.
Egyptian President Abdel Fattah al-Sisi and Sudan's transitional leader Abdel Fattah al-Burhan, at a meeting Tuesday in Cairo, called for a "legally binding accord" on the dam, a demand that Ethiopia has resisted.
The talks have been suspended since August.
Construction for $4bn Grand Ethiopia Renaissance Dam (GERD) began in 2011 and has suffered several delays.
Addis Ababa sees the dam as critical to its efforts to industrialize and and to fight poverty.
The US announced last month it was suspending a portion of its financial aid for Ethiopia, citing a lack of progress in talks and Addis Ababa's "unilateral decision" to start filling the dam's reservoir.
Sudan and Egypt have long called for a political solution to the dispute, rejecting any unilateral action by Ethiopia.