CAIRO — Egypt wants "formal agreements" that Ethiopia will not reduce Cairo's share of the Nile during the filling of what will be Africa's largest hydroelectric dam.

President Abdel-Fattah el-Sissi told reporters Tuesday that "we need to turn Ethiopia's goodwill into formal agreements" and ensure the dam is not used for "political purposes." He did not elaborate, saying only that Egypt has seen "positive signs" from Ethiopia's government.

Egypt fears the $4.8 billion dam could reduce its share of the Nile River, which provides virtually all its freshwater. Ethiopia says it needs the dam for its economic development.

The two have been at odds over how quickly the reservoir behind the dam will be filled and the impact it would have on Egypt's share of the Nile.