Sudan said on Tuesday a notification by Ethiopia on the start of the second filling of its mega dam on the Blue Nile is“useless” unless a final agreement on the process is reached.

The Sudanese foreign ministry said a final binding agreement on the filling and operation of the Grand Ethiopian Renaissance Dam (GERD) would be “the only proof of the Ethiopian desire in cooperation,” state-run Sudan News Agency (SUNA) reported.

Sudan also slammed attempts to block the path of international support to the fair Sudanese demands on the GERD dispute as “futile”.

The ministry reiterated its rejection of Ethiopia’s unilateral step to start filling the dam for the second year in a row.

Such step represents an “explicit violation” of the international law, the Declaration of Principles (DoPs) and the established principles and agreements regulating the exchange of benefits of common rivers, the ministry stated.

The DoPs is an agreement signed between Sudan, Egypt and Ethiopia in March 2015 that obliges Addis Ababa to cooperate with Cairo and Khartoum in filling and operating the dam.

The agreement also mandates the use of mediated negotiations in the event of a dispute arising from differences in its interpretation or application.

“Sudan reaffirms that the unilateral filling [of the dam] for the second year without an agreement constitutes an imminent danger and threat to Sudan,” the ministry added.

Sudanese Foreign Minister Mariam Al-Sadiq, currently in New York, notified the United Nations Security Council (UNSC) of Ethiopia’s unilateral move, the ministry said.

The ministry added that such step from the Ethiopian side would aggravate tensions and instability in the region.

Al-Sadiq met with Egypt’s Foreign Minister Sameh Shoukry on Monday evening in New York as they are both set to take part in the UNSC session scheduled for Thursday over the GERD dispute.

Their meeting came only hours after Addis Ababa also notified Egypt in a letter on Monday that it has begun the second stage of filling the GERD's reservoir despite the lack of a legally binding agreement between the three African nations.

Ethiopia’s latest step brushes aside Egyptian and Sudanese demands of the need that a legally-binding agreement on the filling and operation of the dam is reached before the second filling.

Shoukry and Al-Sadiq voiced their “categorical” rejection of Ethiopia’s announcement, saying it reveals Ethiopia's “ill” intention to impose a fait accompli on downstream countries and indifference to the foreseeable negative impacts and damages, according to a statement released by the Egyptian foreign ministry on Tuesday.

Both ministers also said the unilateral filling represents a “blatant” violation of the DoPs agreement and a violation of international laws and norms governing the exploitation of trans-boundary river resources, the statement added.

Shoukry and Al-Sadiq agreed on continuing to intensify contacts and consultations with the UNSC members to urge them to support the position of Egypt and Sudan, which is based on reaching a legally binding agreement that takes into account the interests of the three countries.

Over the past few hours, both ministers held several talks with their counterparts, permanent delegates of the UNSC’s member states, and UN officials.

The talks took place during meetings and phone calls with African and Arab representatives at the UNSC, in addition to others.

In remarks to Saudi broadcaster Al-Arabiya, Shoukry said both Egypt and Sudan are capable of defending their water interests, reiterating that “all options are open”.

The minister said the GERD negotiations cannot run indefinitely and that Egypt resorted to the Security Council in pursuit of reaching a GERD agreement.