Prime Minister Hesham Kandil had just finished addressing parliament about how the government planned to work diplomatically, legally and technically to negotiate with Ethiopia over the dam when the session heated up.
He called the dam's construction an "act of defiance" and stressed that Egypt will not give "a single drop of water," but then hurriedly left the chamber despite calls for clarification over how to handle the situation if Ethiopia rejects overtures.
"Egypt will turn to a graveyard" if the dam is completed, geologist and Egyptian lawmaker Khaled Ouda shouted to parliament. "The prime minister didn't provide anything."
"We have to stop the construction of this dam first before entering negotiations," he said.
The crisis started when Ethiopia diverted the flow of the Blue Nile, one of the Nile's sources, to make way for the dam last month before a 10-member panel of experts from Egypt, Sudan, Ethiopia and other countries released a study on the dam's impact. The move took the Egyptian government by surprise. Eighty-five percent of the Nile's water comes from Ethiopia.
Egypt in the past has threatened to go to war over its "historic rights" to the waters of the Nile River. Last week, Egyptian political leaders caused uproar after proposing to aid rebels against the Ethiopian government or even sabotaging the dam itself. Ethiopia demanded an official explanation.
Egypt faces the prospect of its current water shortage worsening when the so-called Grand Ethiopian Renaissance Dam is completed.
Ethiopia's decision challenges a colonial-era agreement known as that had given downstream Egypt and Sudan rights to the Nile water, with Egypt taking 55.5 billion cubic meters and Sudan 18.5 billion cubic meters of 84 billion cubic meters, with 10 billion lost to evaporation. That agreement, first signed in 1929, took no account of the eight other nations along the 6,700-kilometer (4,160-mile) river and its basin, which have been agitating for a decade for a more equitable accord.
Ethiopia's unilateral action seems to ignore the 10-nation Nile Basin Initiative, a regional partnership formed in 1999 that seeks to develop the river in a cooperative manner.
Ethiopia is leading a group of five nations threatening to sign a new cooperation agreement known as the Entebbe Agreement without Egypt and Sudan, effectively taking control from Egypt of the Nile, which serves some 238 million people.
In another blow to Egypt, newly independent South Sudan said it too would join the agreement. Foreign Minister Deng Nhial Deng told reporters the move was necessary.
"South Sudan has no choice but to become a member of the Entebbe Agreement," he said, adding that his government had informed Egypt of the decision. "The bottom line is that we have nothing to fear from being part of the Entebbe Agreement," he said. Adding to Egypt's worries, he said South Sudan is envisioning long-term projects that it expects will face opposition from Egypt.
Experts estimate that Egypt could lose as much as 20 percent of its Nile water in the three to five years needed for Ethiopia to fill a massive planned reservoir.
"We need immediate steps day by day but the pace of the government is slow," said Alaa el-Zawahri, a dams engineer at Cairo University and an expert on a national committee studying the ramifications of the Ethiopian dam. "The prime minister's talk should be sharper in the face of Ethiopian government's fiery comments."
Abdullah Badr, who leads the ultraconservative Salafi caucus in parliament, held up a blank notebook after Kandil's speech and said: "I have been taking notes and the page for solutions is blank."
"Where are the studies? Where are the solutions?" He added. "There is nothing more dangerous than this. This is about water security and there are enemies outside and inside what is the role of the government and what did it do?" he said.
Ethiopian officials have downplayed the effect the dam will have on Egypt, saying it is needed to provide much-needed power for the country's development.
Sudanese Ambassador to Egypt Kamal Eddin Hassan said on Sunday that Sudan would benefit from the construction of the dam, but that it would not "abandon" Egypt despite reports in the Egyptian press that Egypt's southern neighbor had allied itself with the Ethiopian project.
"There are benefits to Sudan from the dam but this will not propel it to immediately give its approval," he said, speaking at the Sudanese cultural center in Cairo. He added that Sudan expressed reservations related to the safety of the dam and its negative environmental impact.
The United Nations High Commission for Refugees has warned that the dispute had brought trouble to Ethiopian refugees in Egypt, who had reported assaults and harassment by employers and state administration.
"The commission expresses its worries because of these complaints, and calls upon the public opinion in Egypt to provide physical security protection and other rights to Ethiopian refugees," UNHCR said. There are more than 2,500 registered Ethiopian refugees in Egypt, it added.
Charlton Doki contributed to this report from Juba, South Sudan.