Law professor Kais Saied and detained media mogul Nabil Karoui won the most votes in the first round of Tunisia's presidential election and will contest a runoff vote, the independent electoral commission (ISIE) said Tuesday.

Saied won 18.4 percent of votes, Karoui 15.6 percent and Abdelfattah Mourou of the moderate Islamist Ennahda party came third in a crowded field of 26 candidates with 12.9 percent, the commission said in a televised statement.

Prime Minister Youssef Chahed, a presidential hopeful whose popularity has been tarnished by a sluggish economy and the rising cost of living, could well turn out to be the election's biggest loser.

ISIE figures showed him in fifth place with 7.4 percent of the votes, trailing both Islamist-inspired Ennahdha party candidate Abdelfattah Mourou and former defense minister Abdelkarim Zbidi.

"The anti-system strategy has won," ISIE member Adil Brinsi told AFP, adding that, "It's not finished yet. Mourou could very easily move from third to second place, in front of Karoui."

A smiling Saied, receiving journalists at a rented apartment that serves as his campaign offices, said voters had "carried out a revolution within a legal framework... They want something new... new political thinking."

It was up to civil society and democracy at the local administrative level to resolve Tunisia's social problems, he said while defending his own reputation as a conservative.

Local papers splashed photos of Saied and Karoui across their front pages on Monday.

"Political earthquake," read the headline of Arabic language Echourouk newspaper, while Francophone Le Temps entitled its editorial "The Slap."

The result was a major upset for Tunisia's political establishment, in place since the uprising eight years ago that ousted dictator Zine El Abidine Ben Ali.

It could usher in a period of uncertainty for the country.

ISIE reported low turnout at 45 percent, down from 64 percent in the country's first democratic polls in 2014.

The election comes against a backdrop of serious social and economic challenges.

Sunday's vote was marked by apathy among young voters in particular, pushing ISIE's head to put out an emergency call to them Sunday an hour before polls closed.

Distrust of the political establishment runs high in Tunisia, where unemployment is at 15 percent, and the cost of living has risen by close to a third since 2016.

Jihadist attacks have exacted a heavy toll on the key tourism sector. Around 70,000 security forces were mobilized for the polls.

The date of a second and final round between the top two candidates has not been announced, but it must be held by October 23 at the latest. It may even take place on the same day as the legislative polls.

(With input from Reuters, AFP)

(Cover: Presidential candidate Kais Saied waits to cast his ballot at a polling station in Tunis, September 15, 2019. /VCG Photo)