Tunisia - Four years after its revolution sparked the Arab Spring, Tunisia's presidential campaign is nearing its climax on Friday with incumbent Moncef Marzouki facing 88-year-old favourite Beji Caid Essebsi in a runoff.
Ahead of the final day of campaigning for Sunday's landmark second-round vote, jihadists brandished a videotaped threat against the North African country's political establishment.
Essebsi and Marzouki were to hold last rallies later on Friday on the capital's Avenue Bourguiba, a focal point of the 2011 revolution that toppled long-time ruler Zine El Abidine Ben Ali.
Capping off four years of a sometimes chaotic transition, the vote will be the first time Tunisians freely elect their president since independence from France in 1956.
Amid tight security and the closure of main border posts with strife-torn neighbour Libya, almost 5.3 million Tunisians are being called to the ballot boxes. Tunisians abroad started voting on Friday.
The first round, on 23 November, saw Essebsi, who heads the anti-Islamist Nidaa Tounes party, take 39% of the vote.
Marzouki, a 69-year-old former rights activist installed by parliament two months after December 2011 polls, took 33%.
Clear favourite
Nidaa Tounes won parliamentary elections in October and Essebsi has emerged as the clear favourite to be Tunisia's next president.
His party has said it is waiting until after the presidential vote to start the process of forming a government.
The campaign has been marked by mudslinging, with Essebsi even refusing to take part in a debate with Marzouki, claiming his opponent is an "extremist".
Marzouki first came to power with the backing of the moderate Islamist party Ennahda that ruled Tunisia after the revolution and which came second in the parliamentary vote.
It has refused to back a candidate for the presidential vote but Essebsi insists Marzouki represents the Islamists.
Marzouki in turn accuses Essebsi, who served as a senior official in previous Tunisian regimes, of wanting to restore the old guard deposed in the revolution.
He has even suggested that Essebsi's camp was preparing to "win through fraud" in the election, drawing a sharp rebuke from Tunisia's electoral commission.
Results are expected to be announced between 22-24 December.
In an Internet video posted on Wednesday night, jihadists who joined the Islamic State of Iraq and Syria (ISIS) group claimed the 2013 murder of two secular politicians that plunged Tunisia into crisis, warning of more killings of politicians and security forces.
Interior ministry spokesperson Mohamed Ali Aroui defiantly brushed off the threat, saying: "Tunisians are stronger than these terrorists. They mean nothing to us."
The 2013 murders had threatened to derail Tunisia's post-Arab Spring transition until a compromise government was formed in January this year.
Extra troops, police
In the video posted on Thursday, jihadist Abou Mossaab called on Tunisians to boycott the polls, saying the authorities "are turning you into infidels with these elections".
The government, which has been on alert since October, will be deploying tens of thousands of troops and police to guarantee security during the vote.
Shafik Sarsar, head of Tunisia's electoral commission, recognised there were "possible and probable dangers" but added that this "should not change the atmosphere of the elections".
In addition to the jihadist threat, major challenges remain for Tunisia.
The country's economy is struggling to recover from the upheaval of the revolution and there are fears that widespread joblessness will cause social unrest.