An Egyptian court on Tuesday stopped Parliament's decision to create a new constitution-writing assembly, challenging the legitimacy of a body that has been criticized for its domination by Islamists.
The Cairo Administrative Court halted the "implementation of the decision by the Parliament's speaker to form the Constitutional Assembly to draft the constitution," Judge Ali Fekry told the court.
The court will later decide whether the assembly makeup is legal or not.
Islamists in Parliament have insisted on having MPs on the constitution-writing panel, but liberal voices backed by legal experts said lawmakers' writing a constitution is unprecedented.
Tuesday's verdict can be appealed. Once the verdict is issued by the higher court, the verdict would be final.
The verdict followed a lawsuit decrying the domination of Islamist political group on a large portion of the panel’s 100 seats.
The court's decision could delay the introduction of a constitution needed urgently to clarify the powers of Egypt's new head of state, due to take over from the ruling generals by mid-year.
The government and Parliament had argued that the court had no authority over the move to form the Constituent Assembly.
But Fekry said the court "rejected the argument that the court is not specialized and decided to halt the decision" that formed the assembly. He passed on the case's documents to a judicial panel for a review.
This case is one of several lawsuits that had demanded the dissolution of the assembly because it did not represent the diversity of Egyptian society.
Lawyer Khaled Abu Bakr said the court's capacity to review the case rested on whether Parliament's step to form the assembly was legally seen as an administrative decision.
"This means the assembly's activities are frozen; it is suspended until further notice, until the judicial panel convenes," he said.
Selected by Parliament, the 100-member constitutional assembly is composed mostly of Islamists, who won the majority of seats in Egypt's first free parliamentary vote in decades.
Only a handful of seats were reserved for youth groups, women and for Christian Copts, who said they plan to boycott the assembly, following the example of liberal groups and the country's highest Sunni Islamic institution, Al-Azhar, which withdrew from the assembly.
The current constitution was suspended by the army rulers in February last year, shortly after they took power from Egypt's long-serving autocratic president, Hosni Mubarak, who was forced out by a popular uprising.
The new document is expected to include more freedoms and define rules for the authorities including setting out the terms of presidential power.
It could also decide which institution of state will effectively rule the Arab world's most populous country.
Correction: A previous version of this story incorrectly stated that the Administrative Court had ruled the Constituent Assembly illegal.