Tunisian security forces fired in the air on Sunday in an unsuccessful attempt to disperse tens of thousands of demonstrators in the capital calling for a new interim government, a Reuters witness said.
It was the second straight day of mass protests in the North African country's main city, in defiance of a government ban on rallies, after a lull following the popular uprising last month which led to the ouster of President Zine al-Abidine Ben Ali.
After weeks of relative calm, as many as 40,000 marchers gathered in front of the prime minister's building shouting slogans such as "Leave!" and "We don't want the friends of Ben Ali!" Others were demanding pay raises.
Security forces fired several times in the air, while two military helicopters circled low over the rally, the witness said.
The protesters remained in place and there was no sign that anyone had been injured in the fray.
More than a month after Ben Ali's departure, an event that sparked a wave of protests throughout the Arab world, some Tunisians accuse the caretaker government, charged with holding new elections, of failing to provide adequate security amid a surge in crime, and doing little to help the poor.
The Interior Ministry said on Saturday that mass demonstrations were forbidden under state of emergency laws and protesters could be arrested.
More than 15,000 protesters clogged central Tunis on Saturday, most of them chanting anti-Islamist slogans after the murder of a priest the government blamed on "a group of terrorist fascists with extremist tendencies", and a series of Islamist protests against brothels.
The two days of protests end a stretch of relative calm in the capital that has lasted since early February.
Ben Ali, who came to power in 1987, had outlawed Islamism and was seen as repressive and corrupt by many Tunisians. He fled to Saudi Arabia where he is in ill health, according to sources.
Protests began in Tunisia in late December when police prevented an unemployed graduate from selling fruit without a license and he set fire to himself, dying shortly afterwards of his burns.
For decades, Tunisia has promoted itself as an Arab world success story, a place where the economy is stronger than in neighboring countries, women's rights are respected, unrest is rare and European tourists can take stress-free vacations at beach resorts.
But the protests exposed a side of Tunisia that the country has long tried to hide: the poverty of the countryside, poor job prospects for youths and seething resentment at the government of President Zine El Abidine Ben Ali, who ruled Tunisia with an iron fist since 1987.
Groups including the International Monetary Fund have praised Tunisia for holding up relatively well during the global economic crisis, and the country had growth of 3.1 percent in 2010, according to government figures.
Unemployment is the weak spot, at nearly 14 percent last year.
It's also worse for educated youths. In a country where schooling has been emphasized for decades, 80,000 educated graduates enter the job market every year, and there isn't enough work for them.