Eighteen political parties and groups have called on Egyptian President Mohamed Morsi to withdraw the constitutional declaration he issued on Thursday and to reformulate the Constituent Assembly, to overcome what they describe as the domination of Islamists within the constitution-drafting body.

On Thursday, Morsi, who hails from the Muslim Brotherhood, issued a decree making all his decisions immune from legal challenges for a six-month period. The decree also protects the Islamist-led Constituent Assembly (tasked with drafting a new constitution) and the Shura Council (the upper house of parliament) from dissolution by court order.

Morsi's surprise decree prompted uproar among the opposition, who described it as an attack on democracy. Thousands demonstrated against the move on Friday in Cairo and several other governorates.

The groups, who announced their demands at a news conference on Monday, also called on Morsi to form a "serious" transitional justice mandate, instead of giving the prosecutor general exceptional powers. In the decree, Morsi ordered the reinvestigation of cases involving the killing of peaceful protesters during and after the 25 January uprising.

More than 30 members of the 100-members of the Constituent Assembly withdrew from the body over the past four weeks in dissent over the draft constitution, including representatives of all Christian churches in the assembly.

Earlier this week, the same groups called for mass demonstrations across the country on Tuesday to protest Morsi's decree and the Constituent Assembly.

Signatories include the leftist Popular Alliance, the liberal Constitution party, the Socialist Popular Alliance party, the Egyptian Social Democratic party, the Karama Party, the Free Egyptians party, the April 6 Youth Movement (both fronts), the Egypt Freedom party, the National Association for Change, the Revolutionary Socialists, the National Front for Justice and Democracy, the Maspero Youth Union, the Youth for Justice and Freedom movement, the Free Egyptian movement, the Kefaya movement, the Free Front for Peaceful Change movement and the Lotus Revolution movement.