as the president pledged the dam would begin generating power in the next 12 months.

The move could worsen Ethiopia's dispute with Egypt and Sudan over its $4 billion Grand Ethiopian Renaissance Dam, which Cairo has said could threaten its main supply of water.

"All flights have been banned to secure the dam," the director-general of the Ethiopian Civil Aviation Authority, Wesenyeleh Hunegnaw, told Reuters by phone. He declined to give more details on the reasons.

Later on Monday in a speech to parliament, Ethiopia's president Sahle-Work Zewde said: "This year will be a year where the Grand Ethiopian Renaissance Dam will start generating power with the two turbines."

She also said that work was underway to enable a second filling of the dam within the next 12 months.

In July, Ethiopia said it had achieved its first year of filling the dam thanks to rainfall in the area.

Ethiopian Prime Minister Abiy Ahmed told the United Nations last month that the country has "no intention" of harming Sudan and Egypt with the dam, days after Egyptian President Abdel Fattah al-Sisi reiterated his concerns over the project. [L2N2GM1RF]

Last week, air force chief Major General Yilma Merdasa told local media that Ethiopia was fully prepared to defend the dam from any attack.

Ethiopia, Egypt and Sudan failed to strike a deal on the operation of the Grand Ethiopian Renaissance Dam before Ethiopia began filling the reservoir behind the dam in July.

The dam is at the centre of Ethiopia's bid to become Africa's biggest power exporter.

The structure is about 15 km (9 miles) from the Ethiopian border with Sudan on the Blue Nile - a tributary of the Nile river, which gives Egypt’s 100 million people about 90% of their fresh water.

The United States decided last month to cut $100 million in aid to Ethiopia amid the dispute over the dam. A U.S. State Department official who did not want to be identified told Reuters at the time that the decision to pause some funding to Ethiopia was triggered by concern over Ethiopia's unilateral decision to start filling the dam before an agreement.