TUNIS  - Tunisian police fired tear gas to disperse protesters in the northern city of Siliana on Friday after a policeman beat a shepherd, witnesses said, in an incident that sparked anger, as the country celebrate the tenth anniversary of the transition to a full democracy.

Hundreds of protesters burned wheels, blocked roads, and threw stones at the police, who followed the protesters and fired gas, witnesses added.

In the coastal city of Sousse, night clashes took place between police and youths who threw stones at the security forces, who fired tear gas.

Local media said small protest also took place in Karm area in the capital Tunis and that police arrested some protesters.

A decade ago, massive protests against corruption, injustice and the repressive regime toppled the late President Zine El Abidine Ben Ali, after a fruit seller set himself ablaze in the central town of Sidi Bouzid after an altercation with a policewoman.

The Tunisian revolution in 2011 inspired a wave of revolt in Arab countries as people rose up to demand democracy.

A video posted on social media showed a policeman scolding and pushing a shepherd whose sheep had entered the governerate headquarter.

The video caused a wave of anger on social media. Activists said that it is unacceptable to harm the dignity of any citizen, a decade after Tunisians revolted against injustice and oppression.

The Public Prosecution office opened an investigation into the incident.

Despite the incident, Tunisia is an example of peaceful transition in a region struggling elsewhere with violence and upheaval, its economic and social situation worsened and the country became on the verge of bankruptcy and the protests increased.

(Reporting By Tarek Amara Editing by Alistair Bell) ((tarek.amara@thomsonreuters.com;))