Egypt's Islamists are to hold a mass rally in a show of support for a disputed draft constitution on Friday, a day before the final phase of vote on the charter, dpa reported.
President Mohammed Morsi's Muslim Brotherhood has said it will participate in the rally, which will be staged outside a major mosque in Alexandria, Egypt's second biggest city.
The call for the rally has raised fears about new violence between opponents and backers of Morsi.
At least 20 people were injured last week in clashes between both sides in Alexandria after a mosque preacher urged people to vote for the constitution drafted by an Islamist-led constituent assembly.
The April 6 Movement, a key protest group, called on its followers to stay away from the site of the rally to head off possible violence.
The secular-minded opposition has said the proposed constitution could undermine women's and political rights, and sideline minorities. referendum
Around 57 per cent of voters in the first round of the referendum on the charter approved it, according to unofficial results.
If the constitution is finally adopted, it will clear the way for legislative elections within 60 days.
If it is voted down, Morsi will call an election within three months to pick a new assembly to draft a new constitution.