The demonstrators attacked the Ennahda party's headquarters in the poor central region after trying to break into the regional governor's office, where they were dispersed by police.
The protesters seized files and furniture from the office and burned them in the road, while preventing firemen from gaining access to the building.
There was no immediate sign of the police.
As in the other regions of Gabes and Siliana, Gafsa ground to a halt today as a general strike was observed.