Islamic State have claimed responsibility for a suicide bomb attack on a Tunisian presidential guard bus on Tuesday that killed at least 13 people.
Tunisian authorities said a suicide bomber carried out the attack yesterday killing at least 12 people and forcing the government to impose a nationwide state of emergency.
ISIS have claimed a militant identified as Abu Abdullah al-Tunisi smuggled a bomb onto the vehicle to slaughter "apostates".
In a statement released through its official news outlet, the Al-Hayat Media Center, the terrorist group claimed responsibility for the attack against the secular Tunisian government.
"The tyrants of Tunis will not have peace and we will not rest until the law of God governs in Tunis," they added.
The explosion on a main boulevard in the capital drove home the vulnerability of Tunisia to Islamist militancy, following gun assaults on a seaside tourist hotel in June and the Bardo Museum in Tunis in March, both claimed by Islamic State.
The country's president has declared a month-long nationwide state of emergency in light of the attack.
"This [bus bombing] is an evolution in the behaviour of the terrorists, this time they attacked a symbol of the state and in the heart of the capital," Prime Minister Habib Essid told reporters.
It was the first suicide bombing in the capital. In October 2013 a bomber blew himself up on a beach in Sousse, and previously an al Qaeda suicide bomber attacked the synagogue in Djerba, killing 21 people.
An Interior Ministry statement said 12 guards died in the blast of 10kg of explosive located either in the bomber's backpack or a belt he was wearing. Another body at the scene was probably that of the bomber.
Around Tunis on Wednesday, troops and armed police patrolled the city streets and set up checkpoints searching vehicles and pedestrians. Only those with booked flights were allowed to enter the Tunis international airport.
"According to the preliminary details, the attacker was wearing a bag on his back. He had on a coat and was wearing headphones. He blew himself up just getting into the door of the bus with military explosives," Hichem Gharbi, a presidential security official, told local Shems FM radio.
One of the most secular Arab countries, Tunisia has enjoyed relative stability since its uprising compared with neighbours Libya and Egypt. It has a new constitution, held free elections and established compromise politics between secular and Islamist parties that has allowed some progress.
But fighting Islamist militants has become a major challenge for a country heavily reliant on tourism for its revenues.
In the early chaotic days after its revolution, ultra-conservative Islamists gained ground, recruiting among young Tunisians and taking over mosques.
More than 3,000 Tunisians are now fighting for Islamic State or other militant groups in Iraq, Syria and neighbouring Libya. Some have threatened to return to stage attacks in Tunisia.
The gunmen in the Sousse hotel and Bardo Museum attacks were all trained in jihadist camps in Libya.
The Tunis government has cracked down on hard line preachers and taken back mosques. It is also building a security wall along the border with lawless Libya to try to stop militants crossing over into its territory.
Additional reporting by Reuters.
