Tunisians cast their ballots Sunday in the second and final round of a landmark presidential vote that marks the culmination of a rocky transition to democracy.
Preliminary results have not been released, but candidate Beji Caid Essebsi's anti-Islamist party quickly claimed victory over his rival, interim president Moncef Marzouki. Essebsi's campaign manager said initial indications showed a victory for the 88-year-old former minister.
Marzouki's campaign manager dismissed the claims, saying the election is too close to call.
Results are expected early this week.
Essebsi, who led the first round of presidential voting in November, heads the anti-Islamist Nidaa Tounes party. It won the most seats in parliamentary elections in October.
The party is a loose coalition of trade unionists, businessmen and former members of the pre-revolutionary government. That includes Essebsi, who served under ousted President Zine El Abidine Ben Ali and his predecessor, Habib Bourguiba.
Essebsi's rival, 75-year-old Marzouki, was a human rights activist who went into exile during the Ben Ali regime. He has been part of a coalition government with the moderate Ennahda party that ended earlier this year. He counts on backing from the Islamists in the runoff.
Marzouki cast his ballot early Sunday in the Tunisian coastal city of Sousse.
Marzouki vowed to respect basic rights - and to ensure the country's democratic transition and revolution would continue. He says Tunisia is a bright spot in the Arab world, and if it goes back to the old era, this pioneering spirit will end.
Just hours before the polls opened, troops guarding ballot papers in the central region of Kairouan came under attack by armed gunmen. Defense ministry officials say troops shot dead one assailant and captured three others.
The campaign has been marked by negative campaigning. Marzouki has accused Essebsi of wanting the restore the old guard ousted in the revolution. For his part, Essebsi has described Marzouki as an "extremist" whose three-year tenure as president has been disastrous. Essebsi refused to hold a debate with Marzouki ahead of the runoff.
If Essebsi wins the presidency, his party will control all the key parts of Tunisia's government. But Ennahda and the Islamists still remain a powerful political force.
In an interview with France 24 news channel ahead of the elections, Essebsi said Nidaa Tounes will be seeking coalitions with like-minded parties to reach a majority in parliament.
Under Tunisia's new constitution, the president has a limited role: responsible for security, defense and foreign affairs. The parliament will determine the key choice of the country's next prime minister.
For many Tunisians, the elections are about bread-and-butter issues.
In the capital, Tunis, one voter, Sihem, said she hoped the country's next president will support the country's youth, fight unemployment and restore security.
The revolution has upended Tunisia's economy and shattered a once stable police state. Tourism and foreign investment have plummeted. Joblessness has soared. So has insecurity, with the country now grappling with militant Islam. Jihadists have threatened to disrupt the runoff on Sunday.