Supporters of former Maldives leader Mohamed Nasheed protesting against the cancellation of elections by police are demanding the resignation of President Mohamed Waheed.
Ex-president Nashjeed looked set to win a run-off presidential vote on 28 September after winning the first round three weeks earlier.
The election re-scheduled for yesterday had been cancelled by the Supreme Court, citing first-round fraud.
But despite confusion over whether the vote could proceed after another court ruling, police stopped the poll, the archipelago's Election Commission said.
The Indian Ocean chain of tropical holiday islands has been in turmoil for almost two years.
Former president Mr Nasheed - who won the Maldives' first free elections in 2008 - was ousted in February 2012 in disputed circumstances, which his supporters insist was a coup.
Mr Nasheed, who once held a cabinet meeting underwater with ministers in scuba gear to highlight the danger of rising sea levels, won the 7 September first-round poll.
He gained 45% of the vote, short of the 50% however needed to avoid a run-off.
There has been widespread international concern over the crisis.
The former president said he had some support within the military establishment but wanted a calm resolution.
"There are elements within the military who would want to adhere to our calls. But we would like an orderly fashion to these things. Therefore I am still hoping that Dr.Waheed would gracefully resign today or tomorrow, " Mr Nasheed told reporters.
Tension has been high in recent weeks.
Men in masks fire-bombed a television station that backs Mr Nasheed on 7 October.