Egyptian President Abdel Fattah El Sisi said on Wednesday that "all options are on the table" in dealing with the growing crisis of a huge Nile dam being built by Ethiopia.
"I would like to advise our brothers in Ethiopia not to get us into the phase of trespassing on even a single drop of Egypt's water in the Nile," Mr El Sisi said at the inauguration of a new government project on digital documents.
The latest talks between Egypt, Sudan and Ethiopia ended without making any progress, a failure that is likely to stoke regional tension.
The Egyptian Foreign Ministry blamed Ethiopia for the failure of the negotiations held in Kinshasa, the capital of the Democratic Republic of Congo.
It said Ethiopia had again rejected a Sudanese-Egyptian proposal for a quartet of the US, the UN, the EU and the African Union to mediate in the stalled talks.
Ethiopia also dismissed an Egyptian proposal for Congolese President Felix Tshisekedi to take charge of the negotiations with the participation of observers from the EU and the United States, as the case has been for the past year, the ministry said.
Mr El Sisi said Egyptians had every reason to be legitimately worried about the Nile water. "We still prefer co-operation [to end the crisis]," he said.
Egypt is apprehensive that the hydroelectric dam in Ethiopia on the Blue Nile, known as the Grand Ethiopian Renaissance Dam, will significantly cut into its share of the river's water, wiping out tens of thousands of jobs and disrupting the delicate food balance for its 100 million people.
Sudan says Ethiopia must share data on the filling and operation of the dam to avoid deadly flooding in its eastern region and the disruption of its own power-generating Nile dams.