Ethiopia will not take part in the final round of US-sponsored talks this week with Egypt and Sudan on a massive dam project Addis Ababa is building on the Blue Nile, the country's water ministry said on Wednesday.

During the negotiations set to be held on Thursday and Friday in Washington, the three countries were due to discuss and sign a draft deal prepared by the US Treasury Department on the filling and operation of the Grand Ethiopian Renaissance Dam (GERD).

Ethiopia's water ministry said it will not take in the talks as it "has not completed its discussions with domestic stakeholders" on the dam. It added in a brief statement on Twitter that it had told the US treasury "it would not be able to take part in a tripartite conversation."

Egyptian Irrigation minister Mohamed Abd El-Ati arrived in Washington on Wednesday to resume the negotiations, according to state news agency MENA.

Sources told Saudi channel Al Arabiya the reason behind Ethiopia's withdrawal is fears that the signing of the draft agreement might negatively impact Ethiopian Prime Minister Abiy Ahmed's standing in the upcoming national elections, slated for August.

The sources added that the Ethiopian delegation doesn't guarantee that the draft agreement will be accredited by the elected parliament.

Earlier this week, the three countries received a draft deal prepared by the US Treasury on the mechanism of filling and operating the hydropower dam, AFP quoted the Sudanese irrigation minister Yasser Abbas as saying.

The draft contains requirements regarding the safety of the GERD during the operation process and also includes means proposed to resolve the disputes that may arise between the three countries, according to the Sudanese legal negotiator Hisham Kahn.

During talks in Washington earlier this month, Egypt, Ethiopia and Sudan agreed to entrust the US and the World Bank with the preparation of the final agreement on the filling and operation of the GERD to be signed by the end of this month.

US Secretary of State Mike Pompeo said later it could take "months" to resolve the dispute between Ethiopia and Egypt over the massive dam on the Nile.

Ethiopia started constructing its $4.8 billion project on the Blue Nile in 2011 in the northern Ethiopia highlands, from where most of the Nile's waters flow.

Ethiopia aims to become the continent's biggest power exporter by generating more than 6,000 megawatts through the dam.

Egypt however fears that the speed of filling the Ethiopian dam will diminish its share of the River Nile water.