Nobel Laureate and general coordinator of Egypt's main opposition coalition Mohamed ElBaradei urged Egyptians to vote against the constitution in the referendum on Saturday.
"To all Egyptians: listen to the voice of reason, say "no" in order to save Egypt and support the nation," the former Director of the International Atomic Energy Agency posted on his Twitter account.
The member of the National Salvation Front added that an "adoption of divisive draft constitution that violates universal values and freedoms is a sure way to institutionalize instability and turmoil."
The National Salvation Front has protested against the charter which they argue only represents one faction of society.
The first phase of the referendum began on Saturday in ten governorates on the country's new constitution.