Egypt's top court said it was suspending its work indefinitely to protest "psychological and physical pressures" after supporters of the country's Islamist president prevented judges from entering the courthouse to rule on the legitimacy of a disputed constitutional assembly.

The court's decision is the latest turn in a worsening political crisis pitting President Mohammed Morsi and his Islamist allies against the mostly secular opposition.

The standoff began when Morsi issued a package of decrees on Nov. 22 that gave him sweeping powers and extended immunity from the courts to a panel tasked with drafting a new constitution.

The Islamist-dominated panel then raced in a marathon session last week to vote on the new charter's 230 clauses without the participation of liberal and Christian members. The fast-track hearing preempted a decision expected from the court on Sunday on whether to dissolve the committee — a ruling the judges postponed on Sunday.

Morsi on Saturday announced a referendum on the draft charter for Dec. 15, despite opposition protests and questions about the document's legitimacy.

The president's seizure of vast powers has galvanized Egypt's disparate opposition groups, who have united in their demands that Morsi rescind the decrees and create a constituent assembly that is more balanced and inclusive.

Morsi's decrees gave him powers that none of his four predecessors since the ouster of the monarchy 60 years ago ever had.

The draft has a new article that seeks to define what the "principles" of Islamic law are by pointing to theological doctrines and their rules. Another new article states that Egypt's most respected Islamic institution, Al-Azhar, must be consulted on any matters related to Shariah law, a measure critics fear could lead to oversight of legislation by clerics.

Rights groups have pointed out that virtually the only references to women relate to the home and family, that the new charter uses overly broad language with respect to the state protecting "ethics and morals" and fails to outlaw gender discrimination.

Having already held mass rallies last week in Cairo that drew as many as 200,000 people, the opposition parties and activist groups have now called for a march Tuesday on the presidential palace in Cairo's Heliopolis district as a "last warning."

Morsi's supporters countered the opposition rallies with a 100,000-strong rally in Cairo on Saturday to voice their support for the president and the draft constitution.

Islamists boasted their turnout showed that the public supports the push by the country's first freely elected president to quickly bring a constitution and provide stability after nearly two years of turmoil.

'Blackest day on record'

But the dispute has polarized an already deeply divided Egyptian public, and thrown the country — already suffering from rising crime and economic woes — into its worst turmoil since Morsi took office in June as the country's first freely elected president.

The Supreme Constitutional Court called Sunday "the Egyptian judiciary's blackest day on record," describing the scene outside the court complex, with Islamist demonstrators carrying banners denouncing the tribunal and some of its judges.

'The judges of the Supreme Constitutional Court were left with no choice but to announce... that they cannot carry out their sacred mission in this charged atmosphere.'—Supreme Constitutional Court statement

Supporters of Morsi, who hails from the fundamentalist Muslim Brotherhood, claim that the court's judges are loyalists of ousted president Hosni Mubarak, who appointed them to their positions, and are trying to derail the country's transition to democratic rule.

The court statement said the judges approached the court but decided against entering the building because they feared for their safety.

"The judges of the Supreme Constitutional Court were left with no choice but to announce to the glorious people of Egypt that they cannot carry out their sacred mission in this charged atmosphere," the statement said.

The judges also were expected to rule to on the legitimacy of the Islamist-dominated upper house of parliament, known as the Shura Council.

By suspending its work, the court joined the country's highest appeals court and its sister lower court in their indefinite strike to protest what they see as Morsi's infringement on the judiciary.

Most judges and prosecutors in the country have been on strike for a week.