Egypt's ruling Islamists claimed Sunday that preliminary referendum results showed strong backing for a divisive constitution rejected by the secular opposition, hours after polls closed and tallying began.
The Freedom and Justice Party, headed by President Mohamed Morsi before his election, said in a statement that 73.7 percent had voted for the constitution, with votes tallied from almost two thirds of polling stations.
The preliminary results for the referendum's second round are collected from returning officers who oversee the count. Official results are expected within two days.
On the eve of Saturday's polling, clashes in Egypt's second city Alexandria injured 62 people as stone-throwing mobs torched vehicles, underlining the turmoil gripping the Arab world's most populous nation.
Eight people were killed and hundreds more injured in clashes between rival demonstrators on December 5 outside Morsi's presidential palace in Cairo.
Some 250,000 police and soldiers were deployed to provide security during the referendum. The army has also positioned tanks around the presidential palace since early this month.
The proposed charter was expected to be adopted after already garnering 57 percent support in the first round of the referendum a week ago.
The main opposition group, the National Salvation Front, alleged in a statement that ballot fraud had taken place since the polls opened, including reports of laymen posing as judges supposed to oversee the vote.
Morsi's vice president, Mahmud Mekki, whose post is not mentioned in the new charter, announced Saturday that he was resigning.
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"Political work does not suit my professional character," he said in a statement, referring to his past as a respected judge.
State television reported that Central Bank chief Faruq El-Okda had also resigned, but later cited a cabinet source as denying this had happened.
A slim margin and a low first-round turnout in the referendum is expected to embolden the opposition, which looks likely to continue its campaign against Morsi and his Muslim Brotherhood movement.
At one polling station in Giza, southwest Cairo, 50-year-old housewife Zarifa Abdul Aziz said: "I will vote 'no' a thousand times. ... I am not comfortable with the Brotherhood and all that it is doing."
However, 19-year-old law student Ahmed Mohammed said he voted "yes" because "Egypt needs a constitution to be stable."
Rights groups say the charter limits the freedoms of religious minorities and women, while allowing the military, which retains considerable influence over politics, to try civilians it believes "harm" the army.
Morsi had to split voting over two successive Saturdays after more than half of Egypt's judges said they would not provide the statutory supervision of polling stations.
The National Salvation Front launched a last-ditch campaign to vote down the charter after deciding that a boycott would be counter-productive.
But it and Egyptian human rights groups alleged that the first round was marred by fraud, setting up a possible later challenge to the results. They called news conferences for Sunday to give their observations on the second round.
Preliminary tallies from the final round were expected early Sunday. If, as expected, the new constitution is adopted, Morsi will have to call parliamentary elections within two months, to replace the Islamist-dominated assembly ordered dissolved by Egypt's top court in June.