Women and children were caught up in a police siege near the Tunisian capital Friday, with "terrorists" killing one officer in a firefight, ahead of elections that have sparked fears of jihadist attacks.
The confrontation at a home near Tunis erupted Thursday as security was tightened in the lead-up to Sunday's parliamentary vote, the first since the nation's 2011 revolution.
At least two women and two children were inside the house in the town of Oued Ellil where a group was exchanging gunfire with security forces, the interior ministry said.
"There are two children, that's why we haven't launched an assault but there will be an assault in the hours to come," ministry spokesman Mohamed Ali Aroui said.
"We also have information on the presence of explosives," he added.
Sunday's election is seen as crucial to restoring stability in the North African nation, the cradle of the Arab Spring revolutionary movements, and the government has ordered the deployment of tens of thousands of soldiers and police for polling day.
Since the 2011 uprising that ousted veteran strongman Zine El Abidine Ben Ali, Tunisia has seen a proliferation of Islamists suppressed under the former autocratic president and the emergence of militant groups.
The jihadists have been blamed for a wave of attacks, including last year's assassination of two leftist politicians whose murders plunged the country into a protracted political crisis.
The Tunisian authorities gave no indication as to the identity of those involved in the ongoing siege, or whether they were members of any group.
Authorities have demanded that the children and women be allowed to leave the house and the police, using loudhailers, also told the gunmen -- who they described as "terrorists" -- to surrender.
- 'Human shields' -
The government said the gunmen were using the women and children as "human shields," and Aroui said one of the women was the wife of one of the militants.
Police have been besieging the house for hours and gunfire exchanges could be heard intermittently late into the evening.
One policeman was killed in the firefight and another one was wounded.
"Our agent died of a bullet wound in the eye sustained in clashes with a terrorist group," a police official told AFP at the scene.
With security beefed up ahead of the election, Aroui told Mosaique FM radio that police had also clashed earlier Thursday with two "terrorists" in Kebili, 500 kilometres (300 miles) south of Tunis.
The suspects were arrested after killing a private security guard in the gunfight, he said.
The operation in Oued Ellil was launched based on information extracted from the two suspects, Aroui said, adding that the suspects had been "preparing operations in the area".
Jihadists have killed dozens of soldiers and police over the past three years, especially in remote mountain areas on the Algerian border.
Tunisia announced a three-day closure from Friday of the border with politically unstable Libya for fear of possible terrorist attacks on election weekend.
- Tunisia democracy a 'model' -
Rached Ghannouchi, leader of Tunisia's moderate Islamist movement Ennahda, told AFP that the country's transition to democracy served as an example of how to defeat extremists such as the Islamic State group.
"The success of the Tunisian experience is in the international interest, especially in the fight against extremism and the fight against Islamic State and similar groups," he said.
"The Tunisian model is the alternative to the Daesh model," he said, using the Arabic acronym for the Islamic State group which has seized swathes of Iraq and Syria.
"This Tunisian model... brings together Islam and secularism, Islam and democracy, Islam and freedom for women," he said.
Some 2,000-3,000 Tunisians are believed to have joined extremist groups, including Islamic State, fighting in Syria and Iraq. Tunisian authorities fear the return of some of these could move the country towards fresh destabilisation.
Security and the fight against terror have been key planks of the election campaign.
Ennahda headed a coalition government until it stepped down in favour of a caretaker cabinet of technocrats earlier this year to bring an end to months of crisis sparked by the assassination of the opposition figures.