Former Maldives president Mohamed Nasheed won the most votes in Saturday's presidential election on the Indian Ocean islands, but not enough at avoid a runoff.
In the third try since September to elect a new president, Mr. Nasheed won 47 percent of the vote. Abdulla Yameen, the half-brother of former strongman Maumoon Abdul Gayoom, won 30 percent.
All sides agreed that a runoff would be held Sunday. But Yameem is now demanding a postponement saying he needs more time to study voter lists.
Further delays risk sending the country into a constitutional crisis because the next president is due to be inaugurated on Monday, November 11.
U.S. State Department spokeswoman Jen Psaki says it is unreasonable and unacceptable to demand a new runoff date. She said it is essential the next round be held as scheduled for democracy to move forward in the Maldives.
The former president also won a September election, but the Supreme Court tossed out the results. Authorities also cancelled last month's scheduled election.
Mr. Nasheed was elected president in 2008, ending 30 years of autocratic rule in the tourist paradise. He was forced to resign at gunpoint in 2012.