Ethiopia has refused to halt work on a controversial giant dam across the river Nile that Egypt fears will severely curb its water supply.
The refusal came after the Egyptian president, Mohamed Morsi, promised to "defend each drop of Nile water with our blood" and other senior Egyptian politicians called for the dam's destruction.
A spokesman for the Ethiopian prime minister said on Tuesday that Morsi's speech was irresponsible and that the project would proceed as planned.
"Nothing is going to stop the Renaissance Dam. Not a threat will stop it," Getachew Reda said via telephone. "None of the concerns the Egyptian politicians are making are supported by science. Some of them border on what I would characterise as fortune-telling."
Ethiopia hopes its Grand Renaissance dam – which will cost more than $4.3bn (£2.8bn) – will form Africa's largest hydropower plant. But Egyptian authorities have contested its construction after water experts claimed it would drastically lower the level of the Nile, which supplies almost all of Egypt's water, and could reduce cultivated farmland by up to 25%.