Tunisia policeman killed in pre-election clash with militants

Police negotiators in the suburb Oued Ellil to the west of Tunis were trying to persuade militants to give themselves up after the house they were in was surrounded following heavy exchanges of gunfire, officials and a Reuters witness said.

Heavily armed security forces used tear gas and stun grenades to try to force at least two suspected militants out of the house, in which officials said several women and children were being held.

"We've called on them to let the woman and children out, but they refused ... they are family members," interior ministry spokesman Mohammed Ali Aroui told reporters. "We have to move cautiously here."

Tunisia has struggled to subdue hardline Islamists and jihadists opposed to the transition to democracy following the 2011 fall of Zine el-Abidine Ben Ali, and the military has cracked down hard on militants in the run up to the election.

Security and economic development are major concerns for Tunisians voters who hope the poll will consolidate the country's democracy after a year of political disputes that almost scuttled the transition process.

Tunisia on Thursday also closed border crossing points with Libya for most traffic as a security measure, officials said. With Libya struggling to control Islamist militants and armed factions, neighbors like Tunisia are worried about spillover.

Aroui said that as part of pre-emptive raids, security forces also captured two suspected militants in Kebeli in the south of Tunisia who had ties to the group in Oued Ellil.

Earlier this month, security forces arrested a group of Islamist militants, including two women, saying they were planning attacks in the capital before the vote.

Since the 2011 revolt, Tunisia has advanced toward full democracy, unlike the region's other countries where Arab Spring uprisings brought about changes of government.

Among militant groups operating there is Ansar al Sharia, which the United States considers a terrorist organization and blames for a 2012 attack on the U.S. embassy in Tunis.

Prime Minister Mehdi Jomaa said recently Tunisia has arrested some 1,500 suspected jihadists this year, among them hundreds who fought in Syria's civil war and could pose a danger at home.

Four years after street protests forced Ben Ali and his entourage to flee to Saudi Arabia, driven out by anger over corruption and repression, Tunisia's transition has been praised as a model for an unstable region.

But the new government needs to take on the low-intensity conflict with Islamist militants as well with pressure from international lenders to reform public spending subsidies to curb a deficit without stoking social tensions.