Egyptian PM Mostafa Madbouli and Sudanese counterpart Abdalla Hamdok issue joint statement after Khartoum talks.
Khartoum sends letter to UN Security Council after talks also including Addis Ababa and Cairo failed to produce a deal.
Officials confirm satellite images showing water levels rising, amid failed talks with Egypt and Sudan.
Three countries at odds after multiple rounds of talks failed to produce a deal on the operation and filling of the dam.
The plane had been carrying humanitarian and medical supplies to help the country fight the spread of coronavirus.
Foreign ministers of three countries say they have reached an agreement on schedule to fill massive dam on Nile River.
Disagreements over Africa's largest dam project raise fears of conflict.
PM Abiy said his country could ready millions if there is need to go to war over dam project opposed by Egypt.
Immigration ministers of three countries meet in Cairo for talks aimed at resolving dispute over water distribution.
At the heart of the dispute is which country has control over Africa's longest river.