Egypt said on Tuesday that it has decided to withdraw from the latest round of tripartite negotiations with Ethiopia over its multi-billion dollar dam on the Blue Nile for internal consultations after Addis Ababa proposed new draft of filling guidelines.

The Grand Ethiopian Renaissance Dam, which is being built about 15 km from the Ethiopian border with Sudan on the Blue Nile, has become a major sticking point between the three countries. Egypt fears the $4-billion project could lead to water shortages upstream, while Sudan is concerned about the dam's safety.

The Blue Nile is a tributary of the Nile river, from which Egypt’s 100-million people get 90% of their fresh water.

Cairo said Addis presented a proposal on Tuesday that excluded "operating guidelines" as well as "a legal mechanism to settle disputes."

Sudan's irrigation ministry said the latest Ethiopian position presented in talks on Tuesday raised new fears over the track the negotiations had been on.

"[We] stress the seriousness of the risks that the dam represents for Sudan and its people, including environmental and social risks, and for the safety of millions of residents along the banks of the Blue Nile... which reinforces the need to reach a comprehensive agreement covering both filling and operation," the Sudanese irrigation ministry said.

Ethiopia's Irrigation Minister Seleshi Bekele had expressed optimism over the talks and tweeted earlier on Tuesday saying: "Ethiopia would like to sign the first filling agreement at the soonest and also continue negotiation to finalize a comprehensive agreement in subsequent periods."

Ethiopian Prime Minister Abiy Ahmed had said earlier in July that his country had already achieved its first-year target for filling the reservoir, thanks to a heavy rainy season.