Cairo - Ethiopia's prime minister arrived in Cairo on Wednesday for a two-day visit to discuss a massive dam that Egypt fears will cut into its share of the Nile, at a time of heightened tensions among the countries that rely on the river.Hailemariam Desalegn is the highest-ranking Ethiopian official to travel to Egypt to take part in what has become a regular meeting of the "High Joint Commission" to address the issue. He will meet with Egyptian President Abdel-Fattah al-Sisi on Thursday.Egypt's Foreign Ministry announced the visit in a statement that only made passing mention of the dam among other issues. The two countries' foreign ministers held talks ahead of the visit, and Egypt said it was committed to an earlier agreement to share the Nile with Ethiopia and Sudan during the filling of a reservoir behind the new dam."(It) will be, upon its full implementation, a successful model of cooperation in the Nile basin," Egyptian Foreign Minister Sameh Shoukry said in comments carried live on state television.Egypt has expressed mounting alarm over the soon-to-be-completed upstream dam. The Nile provides nearly all the freshwater for the country's 95 million people. Ethiopia, with roughly the same population, has downplayed those fears, insisting the dam is essential to its economic development.Of special concern is the speed at which a planned reservoir is filled behind the dam. Egypt has voiced worries that the filling of the reservoir could drastically reduce the Nile's flow, with potentially severe effects on Egyptian agriculture and other sectors.Ethiopia says the $5bn dam is essential, noting that the vast majority of its population lacks electricity. The dam's hydroelectric plant will generate over 6 400 megawatts, a massive boost to the country's current production of 4 000 Megawatts.Earlier this month, al-Sisi sought to defuse tensions with Ethiopia and Sudan, which has sided with Ethiopia and revived a longtime border dispute with Cairo. Al-Sisi insisted Egypt was not meddling in either country's internal affairs or preparing to go to war.That came after al-Sisi met his counterpart from Eritrea, a bitter rival of Ethiopia which went to war with it in the late 1990s. Ethiopia has accused Eritrea of training rebels to carry out sabotage attacks on the dam.Egypt has traditionally received the lion's share of the Nile's waters under agreements reached in 1929 and 1959. Other Nile basin nations view those agreements as unfair, saying they ignore the needs of their own large and growing populations.