The death toll from demonstrations that have turned violent in Chile has risen to 23, as the country enters its fifth week of social unrest.

Looting and demonstrations took place in cities across the South American nation.

An agreement on a political road map that will see Chile draft a new constitution has halted neither the anger, nor the bloodshed.

Furious Chileans have since 18 October been protesting social and economic inequality, and against an entrenched political elite that comes from a small number of the wealthiest families in the country, among other issues.

The crisis is the worst in three decades of Chilean democracy and has led to around 2,000 injuries, including some 280 people who suffered eye damage from shotgun pellets.

The latest death was a 13-year-old boy who an interior ministry official said was run over by a van during protests in Arica, about 2,100km north of the capital Santiago.

Thousands of people gathered again yesterday in Plaza Italia, the centre of the demonstrations in Santiago and the site of weekly rallies that have seen massive turnout since the social upheaval broke out.

"We cannot ease up. We have to keep expressing ourselves because we have not achieved anything, because the repression continues and also (the government) keeps signing fake agreements, like the peace deal," Claudia Ortolani, a young protester, said.

Nearby, hooded men were squaring off against police, who broke up the crowd with tear gas and water cannons.

Meanwhile, about 100 people protested outside the Costanera Center, the largest shopping centre in South America, as around 20 riot police guarded the entrance to the building.

While protests earlier in the week had not been huge, the outbursts of violence multiplied in the capital's metro area on Thursday and Friday.

The anger in the streets had eased after last week's agreement by Congress to draft a new constitution.

But with people back on the streets in force again, President Sebastian Pinera's government again appealed for calm.

Interior Minister Gonzalo Blumel issued a "deep and sincere call to all political forces" to end the unrest.

But in Quilicura, north of Santiago, a shopping centre was set on fire and looted by a crowd while in Puente Alto, another working-class area, a petrol station, a police headquarters and businesses were attacked.

In the northern city of Antofagasta, a motorist injured five people when he ran down protesters, while a supermarket was ransacked.

Looting, barricades and fires were also recorded in the port of Valparaiso and the city of Vina del Mar, and in Concepcion in the south.

"This situation ... affects our offer to take charge," said police general Enrique Basseletti, after complaints from people irate that they had not seen police on their streets.

Mr Blumel said that 2,500 trainee police officers would be put on the streets early to bolster the force.

On Thursday, authorities arrested 700 people in the unrest. That followed the police decision to suspend the use of birdshot against protesters, following an outcry over eye injury victims.