The approval of Egypt's constitution bolsters the powerful army chief but a large number of youths who helped topple two presidents within three years shunned the vote on the new charter.
Egyptian voters have approved the Tuesday-Wednesday referendum by 98.1 percent, officials announced Saturday, and the results are seen as nod to General Abdel Fattah al-Sisi to run for president.
Sisi led the overthrow of Islamist president Mohamed Morsi in July following massive protests against his one-year rule, which came after an uprising in 2011 toppled his predecessor Hosni Mubarak.
Youth movements at the forefront of protests that ended the rules of Morsi and Mubarak hardly objected when the military-installed authorities launched a deadly crackdown on Morsi's supporters.
Nor did they object when his Muslim Brotherhood movement was banned and designated a "terrorist" organisation.
But they voiced their outrage when the military-backed authorities passed a law in November banning unauthorised demonstrations.
And this appears to have been clearly reflected during the voting.
Sisi had urged the youths to participate in the referendum, saying they formed "more than 50 percent" of Egypt's 85-million strong population.
But AFP reporters who toured polling stations said youths did not participate in the voting in strength and analysts confirmed many young people clamouring for change shunned the polls.
Political analyst Hassan Nafea said turnout was "disappointing".
"The youth refused to participate in the referendum because they consider what is happening as a counter-revolution to the January revolution (against Hosni Mubarak)," Nafea said.
Electoral commission head Nabil Salib announced the results on Saturday and said turnout "reached 38.6 percent" of 53 million registered voters, with only 1.9 percent voting "no."
Salib also acknowledged a certain percentage of youths had not voted as the referendum coincided with exams, otherwise "turnout would have been higher".
But Morsi's Muslim Brotherhood said in a statement young voters "were not busy with exams, but busy with demonstrations against the coup d'etat and the invalid referendum".
The new charter replaces an Islamist-inspired one adopted in a December 2012 referendum under Morsi with about two-thirds of the vote and a 33 percent turnout.
The EU's foreign policy chief, Catherine Ashton, on Sunday voiced approval of Egypt's "largely orderly" referendum, but said she expected it to usher in civilian leadership.
Ashton said the EU could not verify alleged irregularities but stressed that "these do not appear to have fundamentally affected the outcome".
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She added: "I do however strongly regret the violent clashes related to the referendum leading to deaths and injuries on all sides in protests."
Nafea said the result showed, however, support for Sisi to run for president because "a large segment of Egyptians see the Brotherhood as a threat to the society".
Spectre of Mubarak era
Sisi has said he would run for the presidency if there was a popular demand.
The general is wildly popular with the millions who took to the streets against Morsi, but the Islamist's followers revile him for what they say was a "coup" against Egypt's first freely elected president.
The Brotherhood, reeling from a crackdown by the military-installed authorities that has seen thousands of Islamists arrested and more than 1,000 people killed, dismissed the referendum as a "farce".
Many youths agreed, but for different reasons.
"For us it is ironic that the constitution talks of freedom of speech and yet those who said no to the constitution have been jailed," said activist Mohamed Ghorab of the No to Military Trials of Civilians group.
"For many this is a reminder of the previous Mubarak era regime," he said.
Prominent youth leaders from the 2011 uprising against Mubarak have been jailed in recent weeks.
They include Ahmed Maher, Ahmed Douma and Mohamed Adel, convicted in December for organising an unlicensed protest -- days after a law was passed in November banning all but police-sanctioned demonstrations.
These convictions have been denounced by rights groups and experts who says they threaten the gains achieved since the toppling of Mubarak and signal a return of a police state.
The non-Islamist youngsters "who participated in the revolt against Mubarak did not do that for a return to autocracy," said James Dorsey of Singapore's S. Rajaratnam School of International Studies.
On Sunday, in an apparent attempt to appease young Egyptians, interim president Adly Mansour said "the youths... were the engine of two popular revolutions".
"But your role is not over yet... continue on the path and get involved in the political life... you know that freedoms are now guaranteed," he said live on state television.