Tunisian police officers are pictured after an attack on a military bus in Tunis, Tunisia November 24, 2015.

Twelve people were killed and 17 were wounded as a bomb tore through a bus carrying presidential guards in Tunisia’s capital on Tuesday in an explosion described by the president’s office as a “suicide attack,” Al Arabiya News Channel reported.

Essebsi declared a 30-day state of emergency, giving more powers to security forces, in addition to a curfew that would last until 5 a.m. on Wednesday.

Ambulances rushed wounded from the scene and security forces closed off streets around Mohamed V Avenue, one of the major streets in the capital Tunis and where the charred wreckage of the bus lay not far from the interior ministry.

Security sources said the guards were boarding the bus to be taken to the presidential place on the outskirts of the city when the explosion hit. One presidential source said it was likely that a bomber had detonated his explosive belt inside.

“I was on Mohamed V, just getting ready to get into my car, when there was a huge explosion. I saw the bus blow up. There were bodies and blood everywhere,” Bassem Trifi, a witness, told Reuters news agency.

At least 12 guards were killed and 17 wounded, according to an interior ministry statement.

Essebsi cancelled a trip to Europe he had planned for Wednesday.

Mohamed V is a major boulevard usually packed with traffic and pedestrians, and the site of several hotels and banks.

Tunisia has had free elections and is operating under a new constitution and a broad political consensus that has allowed secular and Islamist parties to overcome a crisis that threatens to overturn their young democracy.

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