Tunisians vote Sunday in their first presidential election since the 2011 revolution, a ballot set to round off an often fraught transition to democracy.

Tunisians vote Sunday in their first presidential election since the 2011 revolution, a ballot set to round off an often fraught transition to democracy.

Among the 27 candidates, the hot favorite is former premier Beji Caid Essebsi, an 87-year-old veteran whose Nidaa Tounes party won parliamentary elections last month.

Others vying for the presidency include outgoing President Moncef Marzouki, several ministers who served under former dictator Zine El Abidine Ben Ali, left winger Hamma Hammami, business magnate Slim Riahi and a lone woman, magistrate Kalthoum Kannou.

Some 5.3 million people are eligible to cast ballots, with tens of thousands of police and troops deployed to guarantee security amid fears Islamist militants might seek to disrupt voting.

In most of the country, polls open at 8:00 am (0700 GMT) and close 10 hours later. However, voting will be limited to only five hours in some 50 localities close to the Algerian border, where armed groups are active.

A run-off vote will be held at the end of December if no one secures an absolute majority.

Until the revolution, Tunisia knew only two presidents -- Habib Bourguiba, the "father of independence" from France in 1956, and Ben Ali, who deposed him in a 1987 coup.

To prevent another dictatorship, presidential powers have been restricted under a new constitution, with executive prerogatives transferred to a premier drawn from parliament's top party.