Egypt's top judges said on Monday they would ensure judicial oversight of a referendum on a draft constitution, paving the way for the December 15 vote to proceed despite calls for a boycott by some of their colleagues.
The decision by the Supreme Judicial Council marks a boost for President Mohamed Morsi after he was plunged into his worst crisis since he took power in June when he issued a decree broadening his powers.
On the street, however, agitation is growing, with another protest rally called by the opposition on Tuesday.
The new charter, which was rushed through by an Islamist-dominated panel after the November 22 decree expanding presidential powers, has become the focal point of a political and ideological battle in Egypt between Islamists who support Morsi and the largely-secular opposition.
The latest demonstration is scheduled for 1400 GMT on Tuesday, when a coalition of opposition groups, including Nobel Laureate Mohamed ElBaradei's party, are to rally outside the presidential palace to oppose the charter and the referendum.
"We will see what measures to take," which could include calls for civil disobedience and strikes should Morsi not back down on his decree and the vote go ahead," said Tareq al-Khuli of the opposition April 6 movement.
The Supreme Judicial Council's announcement that judges would after all monitor the December 15 referendum comes as a blow to Morsi's opponents, including members of the Judges Club, an influential body representing judges across the country who said on Sunday they would snub the vote.
The judges' oversight is needed to legitimise the referendum, as has been the case for all votes in Egypt.
Mohammed Gadallah, Morsi's legal aide, told AFP the decision meant that the referendum would after all take place under judicial supervision.
Analysts said the decision by the Supreme Judicial Council indicated a rift within the judiciary but there are likely to be enough officials to monitor the voting.
"Maybe there will not be one judge for every ballot box, but perhaps one judge for every polling booth," said Mustapha Kamel al-Sayyed, a political science lecturer at Cairo university.
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In some quarters, judicial anger at Morsi's decree, which puts his decisions beyond the review of the courts, raged on, with the Supreme Constitutional Court (SCC) beginning an open-ended strike on Monday.
The SCC suspended its work indefinitely due to "psychological and material pressure" following a protest by Morsi supporters that the judges said had prevented them from delivering a key ruling that might have dissolved the panel that drafted the charter.
A senior official from Morsi's Freedom and Justice Party said he did not expect that the protest by judges opposed to Morsi and the new constitution would undermine the referendum.
"I am sure that at the end of the day, the judges will supervise the referendum," Amr Darrag told AFP. "We need 14,000 judges. No one has said that all of them share the same opinion."
The press threw its weight behind the mounting protests against Morsi, with an editorial in daily Al-Shuruq warning: "Beware -- fascism is coming."
"When Islamist protesters surround the SCC headquarters and prevent judges from entering, know that the seeds of a fascist state have been sown," it said of Sunday's demonstration outside the constitutional court.
Eleven independent and opposition party newspapers have declared they will not go to print on Tuesday.
The draft constitution, which is to replace the one suspended after president Hosni Mubarak was toppled in early 2011, has been criticised for failing to protect key rights and allowing a stricter interpretation of Islamic law.
Morsi's supporters accuse the opposition judges of being elitist holdouts from the Mubarak-era who oppose Islamists.
Morsi and his supporters have stressed that his new sweeping powers are temporary pending the ratification of the charter by public vote.
Egyptian expatriates will begin voting on the constitution ahead of time, starting on Saturday when embassies will extend their opening hours, foreign ministry spokesman Amr Roshdy said.