The people of Egypt will continue marching for democracy and building state institutions "in spite of the attempts of some to obstruct it", Essam al-Erian, deputy head of the Muslim Brotherhood's Freedom and Justice Party (FJP), has said.
He denounced calls for delaying the referendum on the draft constitution and going back to the 1971 constitution.
Al-Erian urged the people to read the draft carefully before voting.
"When al-Azhar calls on people to vote, when churches encourage people to vote ... and the National Savlation Front urges its supporters to vote no, there is no room for absurd talk about going back to to the 1971 constitution which the January revolution toppled," al-Erian said in a statement on his Facebook page.
Mohamed ElBaradei, founders' representative of the Constitution Party, urged on Thursday President Mohamed Mursi to go back to the 1971 constitution temporarily until a consensus on the new constitution is reached.
"Read the constitution carefully. Ask about what you find unclear. Refer to law and constitution expers" to comprehend what you do not understand, al-Erian stated.
The first phase of the constitutional referendum will begin on Saturday December 15 in 10 governorates including Cairo, Alexandria, and Giza.