A Chilean teenager has died after being shot in the chest during huge protests against the president, Sebastián Piñera, in the capital.

Local media said the 16-year-old boy was shot near a security barricade as protesters fought police in Santiago on Thursday – the second day of a two-day strike against Piñera, which was marked by violent clashes and sporadic looting.

"The youth died from a bullet impact in the chest. He died in hospital," a police spokesman said.

Local media said witnesses blamed police for firing the shots.

"The death of any citizen is a very serious situation," Rodrigo Ubilla, an interior ministry official, said..

Led by students demanding free education, hundreds of thousands of people have taken to the streets in recent months to call for wider distribution of the income from a copper price boom in the world's leading copper-producing country.

On Thursday, youths blocked roads, threw stones and set fire to piles of rubbish at intersections in Santiago and other cities to block traffic. Police used water cannon and tear gas to defuse the latest social unrest against conservative billionaire Piñera's policies.

The government said more than 1,300 people had been detained since Wednesday and several police officers badly wounded – two of them shot – as violence flared. Dozens of shops and supermarkets were looted, and buses were damaged.

Organisers said around 600,000 people joined Thursday's protests across Chile. Reuters reporters estimated the crowds in the capital alone at around 200,000 people.

Operations at some of the world's biggest copper mines were not affected by the protests, which are also intended to pressure the government into raising wages and revamping the constitution and tax system.

While Latin America's model economy has grown 6.6% this year and is an investor magnet thanks to prudent fiscal and monetary policies, many ordinary Chileans feel they are not sharing in the economic miracle.

Investors, long used to economic stability, are weighing risk, although markets have taken the protests in their stride.

Previous governments have faced one-day national strikes, but this was the first 48-hour stoppage since the 1973-1990 Augusto Pinochet dictatorship. A recent poll showed Piñera to be the least popular president since Pinochet's rule.A major cabinet reshuffle last month, the second since Piñera took power in March 2010, has failed to quell unrest.