Tunisian authorities warned of possible car bombings in the capital Tunis and banned traffic in parts of the city after receiving intelligence reports about potential attacks, the state news agency TAP said on Sunday.
The North African country is under a state of emergency after two deadly Islamist militant gun attacks on tourist sites this year. Armed Islamists also often carry out attacks on the armed forces in remote areas in Tunisia but have not previously attempted mass killings with car bombs.
An Interior Ministry source told TAP that a potential assault involving car bombs and attackers with bomb belts had meant to target strategic points in the capital, without giving further details.
"Orders have been given to intensify patrols and searches by the police and the army in certain parts of the capital and the suburban neighborhoods," TAP said, citing the Interior Ministry source.
Authorities closed off access to the main Avenue Habib Bourguiba in the center of the city and several other main streets, the agency reported.
Four years after its uprising ousted autocrat Zine El-Abidine Ben Ali and inspired the "Arab Spring" protests, Tunisia has a new constitution, free elections and a coalition government with secular and Islamist parties.
But more than 3,000 Tunisians have left to fight for Islamist militant groups in Syria, Iraq and neighboring Libya. Some of those jihadists have threatened to return home and carry out attacks on Tunisian soil.
In March, Islamist gunmen killed 21 tourists in an attack at the Bardo Museum in Tunis, and 38 foreigners were killed in an assault on a Sousse beach hotel in June.