Egypt's highest court has suspended its work indefinitely, intensifying a conflict between some of the country's top judges and the head of state.
The Supreme Constitutional Court's announcement came hours after it postponed a ruling on the legitimacy of an Islamist-dominated panel that drafted a disputed new constitution for the country.
Several thousand supporters of Islamist President Mohammed Morsi gathered outside the Nile-side courthouse in Cairo to prevent judges from entering.
The court said yesterday was "the blackest day in the history of Egyptian judiciary".
Yesterday's developments were the latest in an unfolding confrontation between Mr Morsi and his Muslim Brotherhood supporters on one side, and his mainly secular political opponents and the judiciary on the other.
Mr Morsi adopted sweeping new powers in a November 22 decree that stripped the judiciary of any power to challenge his decisions, so it is unclear what effect any ruling would have.
The Supreme Constitutional Court said it would not convene until its judges could operate without "psychological and material pressure", saying protesters had stopped the judges from reaching the building.
Supporters of Mr Morsi had protested outside the court through the night ahead of a session expected to examine the legality of parliament's upper house and the assembly that drafted a new constitution, both of them Islamist-controlled.
The cases have cast a legal shadow over the president's efforts to chart a way out of a crisis ignited by the November 22 decree, which temporarily expanded his powers and led to nationwide protests. The court's decision to suspend its activities appeared unlikely to have any immediate impact on his drive to get the new constitution passed in a referendum on December 15.
Three people have been killed and hundreds more wounded in protests and counter-demonstrations over the decree.
At least 200,000 of Mr Morsi's supporters attended a rally at Cairo University on Saturday. His opponents were also staging an open-ended sit-in in Cairo's Tahrir Square, the cradle of the uprising that toppled Hosni Mubarak in February last year.
Mr Morsi and the Muslim Brotherhood, which propelled him to power in a June election, hope to end the crisis by pushing through the new constitution hastily adopted by the drafting assembly on Friday. Mr Morsi has called a referendum and urged Egyptians to vote.
"The Muslim Brotherhood is determined to go ahead with its own plans regardless of everybody else. There is no compromise on the horizon," said Hassan Nafaa, a professor of political science at Cairo University.
Outside the Supreme Constitutional Court, Muslim Brotherhood supporters rallied behind the referendum date. "Yes to the constitution", declared a banner held by one protester.
The protest reflected the deep suspicion harboured by Egypt's Islamists towards a court they see as a vestige of the Mubarak era.
The same court ruled in June to dissolve the Muslim Brotherhood-led lower house of parliament. Since then, several cases have challenged the legitimacy of the upper house of parliament and the 100-member constituent assembly that wrote the constitution.
Judges supervise voting in Egypt, so Mr Morsi now needs them to oversee the referendum. Vice-president Mahmoud Mekky has said he is confident the judges will perform that role, though Mr Morsi's critics in the judiciary may call for a boycott.