The Tunisian authorities said they had arrested at least 240 youths when police and protesters clashed violently.
On Sunday riots and violent clashes between Tunisian police and protesters broke out in the capital Tunis and several other cities for the second day in a row, while security forces arrested dozens of young people.
The riots came as the country faced an unprecedented economic crisis and a nationwide lockdown imposed since Thursday to contain the rising coronavirus infections.
Internal security spokesman Walid Hkima said riot police arrested 242 people, mostly teenagers and children, who destroyed property and tried to rob shops and banks in several cities overnight and during the day on Sunday.
A decade after a revolution against poverty, corruption and injustice, Tunisia has made progress towards democracy, but its economic problems have worsened and the country is on the brink of bankruptcy and public services in dire straits.
The gross domestic product (GDP) shrank by 9 percent last year, consumer prices have risen and a third of young people are unemployed.
The main tourism sector, which was on its knees after a series of deadly attacks by armed groups in 2015, was hit with a devastating blow by the pandemic.
Tunisia has registered more than 177,000 coronavirus cases, including more than 5,600 deaths from the disease.
The protesters did not make clear demands during demonstrations – what the authorities called rioting – in at least 10 cities across the country.
In the seedy Ettadamen area of the capital, protesters – most of them teenagers – blocked streets and threw stones at the police. Police fired water cannons and tear gas on Sunday to disperse them.
Clashes also spread to the Mnihla area in Tunis.
The protests pose a challenge to the government of Hicham Mechichi, who has reshuffled his cabinet in an ongoing battle for political influence.
The rural central and southern regions of the country remain hot spots for unrest.
Witnesses told Reuters news agency that protests took place in the central towns of Sbeitla and Kasserine on Sunday, with police chasing protesters and firing tear gas.
In the city of Jelma, under the governor of Sidi Bouzid, police dispersed young people, blocked roads and burned tires to protest their marginalization and poverty.
Further protests took place in the cities of Ras Djbel, Ksar Hlel and Beja.