"The constitution is for all Egyptians. There is no exclusion of any individual or group," Amr Moussa told a news conference.
Mohammed Morsi's supporters "have to show the desire to join the Egyptians in their march ... They must show they are part of this nation and cooperate in taking Egypt out of this chaotic situation."
The new constitution is a significantly amended version of one that was adopted by a predominantly Islamist panel last year.
They often end in violence. "Violence will not solve the problems, it will complicate them. ... We need calm and a quiet and candid movement toward the future," said Moussa, a longtime foreign minister and secretary-general of the Arab League.
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Addressing Morsi's supporters without naming them, he said: "They are acting against the interests of society." Morsi's Muslim Brotherhood has yet to announce whether it will call on its supporters to boycott the Jan. 14-15 vote or rally for a "no" vote.
"We will press on along this road and with resolve and determination," said Moussa.
The official Middle East News Agency, meanwhile, reported today that as many as 200,000 members of the security forces will be assigned to protect polling stations nationwide. It said they will include "combat teams" and reserve forces. Beside the polling stations, it said, they will protect key installations.