Protesters hurled rocks and petrol bombs at police stations, a court house and the offices of secular parties in some of the worst clashes since last year's revolt ousted President Zine al Abidine Ben Ali and launched uprisings across the Arab world.
Salafis blocked streets and set tyres alight in the working class Ettadamen and Sidi Hussein districts of the capital overnight.
By morning, protests had spread to a number of residential districts in the capital and to other cities, posing one of the biggest threats yet to Tunisia's democratic transition.
Stone-throwing youths stopped trams from passing through the capital's Intilaqa district where demonstrators entered mosques and used the loudspeakers to call on Tunisians to defend Islam.
Some 2,500 Salafis were still clashing with police in the area by Tuesday evening, an interior ministry official said, adding that 162 people had been detained and 65 members of the security forces had been wounded trying to quell the riots.
The interior and defence ministries imposed a night time curfew on the capital and seven other areas after Interior Minister Ali Larayedh told parliament he expected the riots to continue in the coming days, stretching security forces.
The clashes came a day after the Spring of Arts exhibition in the upscale La Marsa suburb provoked an outcry from some Tunisians who say it insulted Islam. The work that appears to have caused most fury spelt out the name of God using insects.
"These artists are attacking Islam and this is not new. Islam is targeted," said a youth, who gave his name as Ali and had removed his shirt as he prepared to confront police in Ettadamen. "What added fuel to the flames is the government's silence," said Ali, who did not describe himself as a Salafi.
Officials of the government have condemned the art works that they say were intended to insult and provoke, but said there was no excuse for the outbreak of violence that appeared planned and coordinated and could undermine economic recovery as the tourism and harvest seasons get underway.
Larayedh vowed the police would confront any more acts of violence.
"We have entered a phase in which we may see similar incidents and expect it to continue in the coming days and for the number of arrests to increase," he told parliament.
"These groups will not succeed no matter what they do... We will confront those that attack national security."
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