The head of a panel which has drafted a new Egyptian constitution urged the government and its Islamist opponents Sunday to reconcile ahead of January's referendum on the charter.
The two-day referendum starting on January 14 is expected to ratify the new constitution and usher in elections for a parliament and president to replace president Mohamed Morsi, ousted by the military in July.
Morsi's Muslim Brotherhood movement, which has led persistent protests despite a bloody crackdown, has yet to decide on whether to boycott the referendum or campaign for a no vote.
"They have to show their determination to participate and they will be more than welcome," said Amr Mussa, who headed the panel that drafted the constitution.
Both the Islamists, who officially demand Morsi's reinstatement, and the government should "show their determination to engage in reconciliation unconditionally," he said at a news conference.
More than 1,000 people have been killed and thousands arrested, mostly Islamists, in a police crackdown on Morsi's supporters since his overthrow.
The Brotherhood, which fielded Morsi in the 2012 election that brought him to power, had won every election since an uprising overthrew president Hosni Mubarak in 2011.
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But its once formidable nationwide political network is in tatters with the arrest of much of the movement's leadership and mid-level cadres.
A senior Brotherhood official told AFP the movement had yet to decide whether to boycott the vote or rally supporters to vote down the constitution.
The constitution will replace one suspended by the military when it overthrew Morsi, following days of massive street protests demanding his resignation.
The Islamists say they will continue their demonstrations, as the interim government prepares a massive security deployment to protect the thousands of polling stations.
The interior ministry plans to deploy 200,000 policemen, the official MENA news agency reported.
Under the interim government's timetable, the referendum will be followed by parliamentary and presidential polls to be concluded by autumn of 2014.
Voters in post-Mubarak Egypt have already taken part in two referendums, approving an interim charter and then a constitution drafted by a panel dominated by Morsi's Islamist allies in December 2012.
Analysts expect the new draft constitution to be passed by a majority in next month's vote, although the margin is difficult to predict in deeply polarised Egypt.