Protests that erupted more a week against police abuse in Sejoumi neighborhood of Tunisia's capital spread other poor neighborhoods late on Wednesday.
The protesters gathered in Ettadhamen and Intilaka neighborhoods, blocked roads, burned tires and threw stones at police, as officers chased demonstrators and unleashed tear gas, a Reuters reporter at the scene said.
Protests escalated last week after a video circulated online showed police stripping and beating a young man, triggering widespread anger among the public.
On Tuesday, hundreds gathered in Sijoumi, raising slogans against the government and calling on officials to stop police abuse and punish those involved. They chanted "Freedom, freedom, the police state is over."
A man arrested by police on suspicion of dealing drugs died few hours after being arrested last week. The family accused the police of beating him to death. Tunisia's interior ministry has denied the allegation.
The United Nations human rights office in Tunisia said on Monday it is concerned about repeated allegations of serious violations by the Tunisian police amid violent protests.
Forty-three organizations, including the Journalists Syndicate, unions and the lawyers syndicate and the Human Rights League, called for a massive national protest on Friday to end what they say is police impunity. They said that they filed a lawsuit against the Prime Minister Hichem Mechichi, who is also the acting interior minister.
A decade on from the Arab Spring revolutionary protests against poverty, injustice and police state, Tunisia has made progress towards democracy but its economic problems have worsened, which has led to repeated protests.
During the most recent January protests, the police arrested more than 2,000 people, most of them minors. Human rights organizations said that hundreds of them were subjected to ill treatment and torture.