CAIRO — An association of Egyptian judges called Saturday for courts across Egypt to suspend all but their most vital activities to protest an edict by President Mohammed Morsi granting himself unchecked power by setting his decrees above judicial review until the ratification of a new constitution.
The judges’ strike, which drew the support of the leader of the national lawyers’ association, would be the steepest escalation yet in a political struggle between the country’s new Islamist leaders and the institutions of the authoritarian government that was overthrown last year.
As it spills into the courts and the streets, the dispute also increasingly threatens to undermine the credibility of Egypt’s political transition.
A council that oversees the judiciary denounced Morsi’s decree, which was issued Thursday, as ‘‘an unprecedented attack on judicial independence,’’ and urged the president to retract parts of the decree eliminating judicial oversight.
State news media reported that judges and prosecutors had already walked out in Alexandria, and there were other news reports of walkouts in Qulubiya and Beheira, but those could not be confirmed.
Outside Egypt’s high court in Cairo, the police fired tear gas at protesters who were denouncing Morsi and trying to force their way into the building, the second straight day that protesters took to the streets over the presidential decree, which critics have decried as a return to autocracy.
Abdel Meguid Mahmoud, a prosecutor appointed by Morsi’s predecessor, Hosni Mubarak, declared to a crowd of cheering judges that the presidential decree was ‘‘null and void.’’ He denounced what he described as ‘‘the systematic campaign against the country’s institutions in general and the judiciary in particular.’’
A coalition of disparate opposition leaders including the liberal former UN diplomat Mohamed ElBaradei, the leftist-nationalist Hamdeen Sabahy, and the former Mubarak-government foreign minister Amr Moussa, formed a self-proclaimed National Salvation Front to oppose the decree.
In addition to demanding the dissolution of the constitutional assembly, the group said it would not speak with Morsi until he withdrew his decree.
‘‘We will not enter into a dialogue about anything while this constitutional declaration remains intact and in force,’’ Moussa said. ‘‘We demand that it be withdrawn and then we can talk.’’
As the judges group called for a suspension of the courts, lawyers filed claims demanding that the courts seek to overturn Morsi’s decree, joining the battle between the executive and judicial powers.
Advisers to Morsi, a former leader of the Muslim Brotherhood and Egypt’s first democratically elected president, defended his action, saying he was trying to prevent the courts from disbanding the Islamist-dominated constitutional assembly, which is writing a new constitution. The nation’s top courts had already dissolved the Islamist-led Parliament and an earlier Islamist-led constituent assembly.
The advisers said a court decision on the new constitutional assembly had been expected as soon as next Sunday.
The judges’ group, as well as the newly unified secular opposition, have demanded that Morsi withdraw his decree, and that he disband and replace the current constitutional assembly. Many of the assembly’s non-Islamist members, including secularists and representatives of the Coptic Church, had already quit the body to protest the Islamists’ domination.
The vocal criticism of the assembly threatens to undermine the legitimacy of the ultimate charter, and has only increased the likelihood that the Islamist leaders may seek to pass and ratify it on their own, over the opposition of other groups, further damaging its credibility.
The opposition to the decree has also reinforced the fears of Islamists that judges appointed by Mubarak and the secular opposition were deliberately seeking to derail the process rather than accept their defeats.
Strange alliances were formed in opposition to the decree. Activists and politicians who previously railed against the government of Mubarak cheered Saturday for the Mubarak loyalist who served as public prosecutor: Morsi’s decree sought to replace him.
On Friday night young supporters of the opposition parties set up a tent city for an open-ended sit-in in Tahrir Square, the center of the Egyptian revolt, and the groups have called for a demonstration there on Tuesday.
The Muslim Brotherhood, the Islamist group allied with Morsi, has called for rival demonstrations nearby, raising the possibility of street fights between the two sides.