Tunisian security forces are conducting an anti-terrorism operation against suspected Islamist militants across the country.
The interior ministry spokesman Mohammed Ali Aroui confirmed that two Islamist fighters were arrested in the southern town of Kebili after an exchange of fire with authorities in which a bystander was killed. The men were allegedly planning attacks ahead of parliamentary elections to be held on Sunday.
Police are also surrounding a house in the Oued Ellil suburb of the capital Tunis and have exchanged fire with those inside. A member of Tunisia's security forces was killed in the firefight: "Our agent died of a bullet wound in the eye sustained in clashes with a terrorist group," an official told AFP.
Authorities had warned that Islamist radicals seeking to overthrow the state would attempt to disrupt the elections, according to AP.
Reeling from three years of economic stagnation, Tunisians are expected to vote for the party they believe can boost jobs growth and opportunities.
According to early polling data, the election looks set to be a two-horse race between the Islamist Ennahda party that won the country's first election, and the secular Nidaa Tounes party headed by a former Ben Ali parliament speaker.
Ennahda, which has strong ties to Egypt's Muslim Brotherhood party, has been tainted somewhat by its relatively poor economic legacy while it governed the country from October 2011 until January 2014.
Tunisia has often been cited as the only success of the Arab revolts that swept the region in 2011. With a new Constitution and free elections, it looks like experts have reason to call Tunisia an island of liberty amid the chaos.
However Tunisia has also constantly fed Isis (Islamic State) with foreign fighters, becoming one of the most important source for militants.
Tunisian officials said that at least 2,400 Tunisians have travelled to Syria and Iraq to join Islamic State. Thousands more were stopped by authorities in their attempt. Young people who are still jobless and lament the iron fist of authorities are lured into the self-styled caliphate as true example of fairness and equality, with higher standard of living.
Ennahda has struggled to contain the radical Salafi fringes within the party after appealing to them in the aftermath of the Tunisian revolution.
Officials said that at least 400 Tunisians have returned from the Middle East. Many of them have been arrested, according to the New York Times.