Updated

Nepal's highest court has ordered that the government finish the country's long-awaited new constitution by the Sunday deadline. The decision could force new elections if a political deadlock is not broken.

The Supreme Court rejected the administration's proposal for a three-month extension for the Constituent Assembly charged with writing the constitution.

Judge Khila Raj Regmi issued the order Thursday in response to three writs filed against the government's plan to extend the assembly. It was elected in 2008 with a two-year term, which has already been extended four times.

The assembly is unlikely to finish the constitution by Sunday. The political parties are deadlocked on thorny issues such as marking and naming of the proposed federal states.

Also Thursday, U.N. Secretary-General Ban Ki-moon appealed to Nepali political parties and other actors "to make urgent efforts to preserve the constitution-making process and the gains they have made thus far," U.N. spokesman Martin Nesirky said in New York.