Ex-presidential candidate Ahmed Shafiq said on Sunday that Egypt's president and the Muslim Brotherhood, of which he was a senior leader, must relinquish power immediately to end the ongoing crisis.
The Mubarak-era Prime Minister, who lost to President Mohamed Mursi in June, told London's Asharq Al-Awsat that the entire regime needs to be replaced.
He argued that the number of Mursi's supporters has been greatly exaggerated and is in fact less than one million people.
Shafiq described Mursi's claims that foreign agendas were behind the chaos in Egypt as "nonsense", "irresponsible" and groundless.
He argued that the downfall of the Brotherhood in Egypt will create a domino effect in the region.
Political turmoil erupted when Mursi issued a constitutional decree on November 22 expanding his power and shielding his actions from judicial challenges, and escalated when an Islamist-dominated assembly finished writing a draft constitution.
Opposition forces, including liberal, leftist, socialist and other parties and movements widely condemned the two moves and organized demonstrations demanding the annulment of Mursi's decree and a December 15 referendum on the draft charter.
Clashes between Mursi's opponents and supporters have left at least seven people dead and hundreds injured.
Mursi cancelled the controversial decree on Saturday but issued another that shields itself and other constitutional declarations from court challenges.
The new decree reaffirmed that the referendum on the draft constitution will take place on the scheduled date (December 15).