Tunisian protesters hurl stones at security forces (not pictured), during clashes in Ettadamen in the northwest of the capital Tunis, Tunisia.
Tunisia declared a curfew in the capital and seven other regions following violent protests over an art exhibition.
The government has blamed ultra-conservative Salafi Islamists, who were angered by an art exhibition they say insults Muslims. Protesters clashed with police in Tunis on Tuesday, raising religious tensions in the home of the Arab Spring and piling pressure on the moderate Islamist government.
In some of the worst confrontations since last year's revolt ousted President Zine Abidine Ben Ali and launched uprisings across the Arab world, protesters hurled petrol bombs at officers, blocked streets and set tires alight in the working class Ettadamen and Sidi Hussein districts of the capital overnight.
Salafis, who follow a puritanical interpretation of Islam, denied being involved in the clashes, BBC reported.
The curfew will be in place in the suburbs of Ben Arouss, Ariana and Manouba as well as the cities of Sousse, Monastir, Jendouba and Ben Guerdane.
By morning, protests had spread to a number of residential districts. 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.
An Interior Ministry official on Tunisian state TV said 97 people had been detained during the unrest, including dozens of Salafis and some described as "criminals."
According to the BBC, Justice Minister Nourredine Bhiri said that those behind the violence would "pay a heavy price."
"These are terrorist groups which have lost control, they are isolated in society," he told a Tunisian radio station, per the BBC.
Tuesday's clashes came a day after a group of Salafis forced their way into an art exhibition in the upscale La Marsa suburb and defaced works they deemed offensive.
The work that appears to have caused the most fury and polarized Tunisians spelled 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 and was preparing to confront police in Ettadamen.
In a statement released before the protests, Ennahda, the moderate Islamist party that now leads the government, condemned what it described as provocations and insults against religion but urged its own supporters to respond peacefully.
The violence puts Ennahda in a difficult position.
While Islamists did not play a major role in the revolution, the struggle over Islam's place in government and society has emerged as the most divisive issue in Tunisian politics, and several clashes have erupted in recent months.
Salafis want a broader role for religion in the new Tunisia, alarming secular elites who fear they will seek to impose their views and ultimately undermine the nascent democracy.
Some said the unrest started just two days after al-Qaida chief Ayman al-Zawahiri called on Tunisians to demand the imposition of Muslim religious law, AFP reported.
Reuters contributed to this report.
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