The demonstrators had gathered outside the local government offices demanding a solution to the region’s dire unemployment before heading towards the town centre, as small groups set up roadblocks with burning tyres.
Witnesses said police used tear gas and water cannon and fired warning shots in the air as they came under attack from stone-throwers.
Regional health authority chief Abdelghani Chaabani said eight police were injured in Kasserine as well as another 11 in nearby Thala, a day after clashes on Tuesday in which 20 protesters and three police were slightly hurt.
It comes only days after the fifth anniversary of the revolution sparked by the death of a young university graduate who set himself on fire to protest police harassment and unemployment in the nearby town of Sidi Bouzid.
Wednesday’s clashes in Kasserine took place despite a nighttime curfew imposed only the day before in the town of around 80,000 inhabitants.
Tensions have run high in Kasserine since Saturday, when an unemployed man, Ridha Yahyaoui, 28, climbed atop a power pole near the governor’s office and was electrocuted.
He was protesting after his name was removed from a list of hires for public sector jobs.
A provincial official has been sacked following Yahyaoui’s death.
Late on Wednesday, government spokesman Khaled Chouket announced a series of measures for Kasserine, including the creation of 5,000 new jobs and allocation of 135 million dinars (60 million euros) to build 1,000 social homes.