Belaid had last week accused an-Nahda “mercenaries” of attacking his supporters and on Tuesday warned that militias were being created “to terrorize citizens and drag the country into a spiral of violence.”
His supporters flooded the streets of Tunis and other cities, including Sidi Bouzeid, birthplace of the 2011 revolution, where tear gas was fired as about 200 people tried to storm the police headquarters.
Protesters torched the an-Nahda office near Sidi Bouzeid, ransacked another in Gafsa and set fire to a party office in the northeastern town of Kef.
In Kasserine, on the border with Algeria, hundreds of people calling for “vengeance” took to the streets.
Marzouki deplored the killing in an impassioned speech at the European Parliament.
“This odious assassination of a political leader who I knew well and who was my friend ... is a threat, it is a letter sent that will not be received,” he said, insisting the murder would not plunge Tunisia into violence.
Belaid, whose funeral will be today after the main weekly prayers, was a populist known for his iconic smile and black mustache.
A lawyer who spoke with the working class accent of northwestern Tunisia, he defended human rights, was jailed under Ben Ali, and was a member of executed Iraqi President Saddam Hussein’s legal defense team.