Tunisia has arrested some 1,500 suspected jihadists this year, Prime Minister Mehdi Jomaa told Reuters, part of a security crackdown aimed at safeguarding the North African country's fragile transition to democracy.
Among those held are hundreds of militants who have fought in Syria's civil war and who could now pose a danger at home, Jomaa said, as Tunisia prepares to hold parliamentary elections on Oct. 26 and a presidential poll next month.
Jomaa also cited the political turmoil in neighbouring Libya as a key security threat and said his government had stepped up border cooperation with Algeria, which shares Tunisia's concerns that Islamist militants are using Libyan territory as a refuge.
"Since the beginning of this year, we have arrested about 1,500 terrorism suspects. They will face justice in the coming months, including 500 who will be tried this month," Jomaa said in an interview late on Friday.
"The number of Tunisians fighting in Syria is estimated at about 3,000. A few hundred of them have returned to Tunisia and they have been tracked down and arrested," he said.
Since its 2011 "Jasmine revolution" that ousted autocrat Zine el-Abidine Ben Ali, Tunisia has faced a rise in Islamist militant violence, including attacks on security forces, but Jomaa said such concerns would not derail the elections.
"Despite all the serious threats from jihadists, the elections will be a success and we have put in place security plans to counter any threat," he said.
"We have strengthened the security presence, especially on the border with Algeria and Libya," Jomaa said. "Tens of thousands of soldiers and police are ready to ensure the success of the elections."
The main Islamist party Ennahda and the secular movement Nida Tounes are both expected to do well in the parliamentary election. Ennahda has said it is ready to form a coalition government with its secular rivals including former officials of Ben Ali, for the sake of national unity.
Alarm over Libya
After its revolution, Tunisia saw the rise of hardline Islamist militant groups such as Ansar al Sharia, which the United States brands as a terrorist organisation and blames for a 2012 attack on the U.S. embassy in Tunis.
Since April, Tunisia has also deployed thousands of troops in the Chaambi mountains along its border with Algeria to tackle a small group of militants linked to 'Al Qaeda in the Islamic Maghreb', or AQIM, who are hiding out there.
Jomaa said Tunisia was now sharing information on a daily basis with Algeria in pursuit of the militants.
Tunisia, Algeria and Egypt are all concerned that Islamist militant groups are profiting from the turmoil in Libya, where armed factions of former rebels and their political allies have set up rival governments.
A 2013 militant attack on Algeria's Amenas gas plant was launched from across the border in southern Libya.
"Tunisia is surrounded by jihadist groups in the mountains who coordinate with the terrorists in Libya ... Libya is the main source of arms for jihadists in Tunisia," said Jomaa.
The United States said this year it would give Tunisia about $60 million to help fight militant groups, including financing for explosive detection devices, new boats and training.
Washington has also said it plans to sell Tunisia a dozen Black Hawk helicopters.