KHARTOUM, Sudan

Sudanese Foreign Minister Mariam al-Mahdi on Monday accused Ethiopia of threatening Sudan’s national security over Ethiopian plans to move forward with the second filling of its controversial dam on the Blue Nile, a tributary of the River Nile.

"Ethiopians assaulted Sudan and violated the principle of good neighborliness when they carried out the first filling of the dam last July,” al-Mahdi said in a statement.

She warned that the second filling of the Grand Ethiopian Renaissance Dam (GERD) without an agreement with downstream countries “would threaten the lives of 20 million Sudanese and Sudan’s national security”.

On Sunday, Ethiopian Prime Minister Abiy Ahmed said Addis Ababa will carry out the second filling of the GERD during heavy rainfall months of July and August, a step that has been of concern to Sudan and Egypt.

While Ethiopia says the GERD is key to achieve economic development, Egypt fears that the dam will affect its water share from the Nile, the country’s only source of freshwater.

Sudan has repeatedly warned that the second filling of the dam without a binding agreement would compromise the safety of the Sudanese Roseires Dam and endanger the lives of people living in the surrounding area.

Sudan and Egypt have been pressing for the need to sign a binding agreement on the rules of filling and operation of the GERD, while Ethiopia maintains a guideline would suffice.

Years of negotiations between the three countries have failed to make any breakthrough on reaching an agreement.

*Bassel Barakat in Ankara contributed to this report