President Moncef Marzouki was due to address the situation in Siliana in a televised speech at 1900 GMT. In a repeat of events on Thursday, protesters attacked a police station, hurling rocks and erecting barricades, with the police firing tear gas and chasing the demonstrators through the streets, an AFP journalist reported.
A local representative of the UGTT, Tunisia's main trade union, which had called Friday's demonstration, urged the protesters to disperse. "Go back home, it's dangerous. They will fire on you with live rounds," shouted Abdesattar Manai. A "symbolic" march a few kilometres (miles) towards Tunis earlier drew a crowd of thousands, who took part on foot, in cars and on motorcycles, chanting: "With our souls and our blood we sacrifice for Siliana."