At least 12 people have been killed and an additional 16 injured in Tunisia's capitol of Tunis when an explosion hit a bus carrying members of the country's presidential guard, according to the country's Interior Ministry.
The ministry quickly labeled the explosion a "terrorist act" and Tunisian officials confirmed that current president, Béji Caïd Essebsi, was not with the guard when the attack occurred.
#BREAKING: #Tunisia: Terror attack hits Presidential Guards bus in central #Tunis: 22 killed pic.twitter.com/Sz8IBR9PTl— Amichai Stein (@AmichaiStein1) November 24, 2015
The explosion occurred on Mohamed V Avenue, one of Tunis's busiest thoroughfares, during rush hour when the street was already clogged by heavy rains, according to the BBC.
Additionally, the explosion was said to have happened when the bus was in close proximity to the headquarters of the Socialist Destourian Party, the party of former President Zine El Abidine Ben Ali who fled to Saudi Arabia in 2011 after being forced from office.
It was unknown if the explosion was caused by a bomb or by an incendiary device fired at the bus.
There is a lot of confusion at the scene. An angry cried has gathered.Police are now arriving in numbers. BAT are here— Tunisia Live (@Tunisia_Live) November 24, 2015
Later Tuesday night, President Essebsi declared a "war" against terrorism and declared a 30-day state of emergency across the country while imposing an overnight curfew on the Tunis region. He convened an emergency meeting of his security council Wednesday morning.
The explosion came 10 days after authorities increased the security level in the capital, reacting to recent attacks in Beirut and Paris, deploying security forces in unusually high numbers.
Earlier this month, Tunisian authorities announced the dismantling of a cell it said had planned terror attacks at police stations and hotels in the seaside city of Sousse, about 150 kilometers (95 miles) southeast of Tunis.
And on Monday, it was revealed that former President Marcef Marzouki was the target of a foiled assassination plot.
#attentatTunis La police tente de délimiter un périmètre de sécurité en présence d'un grand nombre de badauds pic.twitter.com/lZuvTLuLmB— inkyfada | إنكيفادا (@inkyfada) November 24, 2015
Tuesday's explosion follows two other deadly terrorist attacks on Tunisian soil in 2015, both of which were perpetrated by militants associated with the Islamic State (ISIS).
On March 18, 22 people were killed when gunmen stormed the Bardo Museum in Tunis. And, a few months later, on June 26, 39 people were killed at a popular luxury beach hotel in Sousse by a single gunman.
Both attacks occurred in locations popular with tourists and many of the dead were foreign travelers, resulting in a drastic hit to Tunisia's tourism industry.
UPDATED (4:45 p.m. EST): Additional details on comments by President Essebsi.