Egypt's Supreme Constitutional Court has said it is halting all work indefinitely in protest at the "psychological pressure" it has faced. Islamist protesters earlier prevented the judges from meeting in Cairo to rule on a draft constitution. The supporters of President Mohammed Morsi wanted to block any ruling that would question the document's legality. The court said that Sunday was "the blackest day in the history of Egyptian judiciary". Sunday's developments are the latest in an unfolding confrontation between President 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 decree on 22 November that stripped the judiciary of any power to challenge his decisions, so it is unclear what effect any Supreme Constitutional Court ruling would have. However, analysts say any ruling opposing his decisions would be a direct challenge and would bolster the opposition campaign to have his decree annulled. Mr Morsi has said a referendum on the draft constitution will be held on 15 December. His opponents say the draft constitution undermines basic freedoms. 'Democratic system' The court issued a statement after demonstrations outside the building prevented judges from getting in. The statement read: "[The judges] announce the suspension of the court sessions until the time when they can continue their message and rulings in cases without any psychological and material pressures." It added: "The court registers its deep regret and pain at the methods of psychological assassination of its judges." The court was scheduled to rule on whether to dissolve both the constituent assembly that passed the draft constitution and the Islamist-dominated upper house of parliament, the Shura Council. However, Mr Morsi's decree was passed with the intention of making any such rulings unenforceable. The president's supporters are wary of the court, as it dissolved an Islamist-dominated lower house of parliament in an earlier confrontation in June. The BBC's Naglaa El Emary in Cairo says the Supreme Constitutional Court was effectively the only high-profile judicial body still working, after most of the courts of appeal halted their work in protest at the 22 November decree. 'Struggle will continue' The draft constitution was rushed through the constituent assembly on Thursday night. After receiving a copy of the document on Saturday, Mr Morsi called on "all Egyptians" to take part in the referendum, whether or not they agreed with the draft. "The world is looking at how Egyptians will build their institutions to establish their democratic system," the president said. His announcement was hailed at a rally in Cairo on Saturday, with the crowds chanting, "The people support the president's decision!" The draft constitution and the recent decree have prompted widespread protests by opponents. Many anti-government activists remain camped out in Cairo's Tahrir Square. "Morsi put to referendum a draft constitution that undermines basic freedoms and violates universal values. The struggle will continue," key opposition figure Mohamed ElBaradei tweeted on Saturday. If approved, the new text will overwrite all constitutional declarations - including Mr Morsi's decree - and a new parliament should be elected within 60 days. Among the historic changes to Egypt's system of government, the draft limits a president to two four-year terms. It also introduces some civilian oversight of the military. The draft keeps in place an article defining "principles of Sharia", or Islamic law, as the main source of legislation. Mr Morsi's supporters point to the fact that he is Egypt's first freely elected president and argue that liberals and secularists do not represent the vast majority of Egyptians. But the extent of Mr Morsi's new powers has raised fears that he might become a new dictator.