Strong Egypt Party, founded by former Islamist presidential candidate Abul-Fotouh, says current political climate is not stable enough to amend constitution.
Representatives of secular forces are expected to dominate the 50-member committee entrusted with writing the final draft of Egypt's new constitution.
Egypt's largest Salafist group says it will join the constitutional review committee in order to defend Islamic 'identity' articles.
Egypt's ultra-conservative Islamist group says it took no part in attacks on churches in Assiut on Wednesday.
Arrest of Brotherhood leadership and police intimidation could explain reduced numbers at Friday's pro-Morsi protests, analysts say.
Hundreds of supporters of ex-President Morsi were killed last week and it seems as if their relatives are being systematically bullied by the government.
Islamist group's leader, Aboud El-Zomor, vows to use only peaceful methods to call for Mohamed Morsi's reinstatement.
Nour, Strong Egypt Party and leftist Popular Alliance Party welcome 12-point initiative rejecting violence as well as exclusion.
Egypt's security apparatus wants to isolate and radicalise the Muslim Brotherhood. This would render the movement vincible.
Polls show that about 24% of Egyptians aren't aligned with police's dispersal operation of pro-Morsi sit-ins, but more than 60% are content.