Two people died, 56 were injured and 450 arrested as clashes broke out in Chile during mass street protests to mark the second anniversary of a social uprising, police said on Tuesday.

Monday's demonstrations throughout the country were to mark the October 2019 protests that sparked political change in the country and led to the start of a process to re-write the Pinochet dictatorship-era constitution.

A man was killed by gunfire during an attempted robbery of a shop in Santiago on Monday while a woman died after falling from a motorcycle, also in the capital.

Most disturbances on Monday took place in Santiago where vandals set up street barricades, attacked a police station, and looted shops and public buildings, a police report said.

Authorities detained 450 people throughout the country, 279 of those in Santiago, while 11 civilians and 45 police officers were injured.

"The numbers are very high," said Marcelo Araya, director of order and security at Chile's Carabineros national police force.

Thousands of demonstrators took to the streets in 50 locations around the country to mark the anniversary of the street protests led by students and sparked by a hike in metro fares.

The unrest that followed left 34 dead and 460 people with eye injuries, including some that lost their sight, from pellets and tear gas fired by police.

Billionaire right-wing President Sebastian Pinera's government came under fire over the at times brutal response from security forces that included some rights violations.

A protester in Santiago brandishes a Mapuche flag during demonstrations to mark the second anniversary of Chile's October 2019 social uprising against inequality A protester in Santiago brandishes a Mapuche flag during demonstrations to mark the second anniversary of Chile's October 2019 social uprising against inequality Photo: AFP / Martin BERNETTI

The protests continued for four months up to the outbreak of the coronavirus pandemic.

Juan Francisco Galli, the interior undersecretary, blamed Monday's violence on opposition candidates for next month's presidential election, leftist Gabriel Boric and centrist Yasna Provoste, for proposing and supporting pardons for detainees that "looted, destroyed everything and threw Molotov cocktails" during the 2019 protests.

"The people responsible for the violence are those that established in our country a sense of impunity, that there are no consequences for violence," said Galli.

The violence contrasted with the peaceful protest by 10,000 people on Plaza Italia, the central square in Santiago that was the hub of the 2019 movement, whose behavior was "largely positive," according to Araya.

That protest lasted around four hours with minimal police presence, although authorities had earlier removed traffic lights and rubbish bins to prevent vandals from damaging them.

Some 5,000 police officers were deployed throughout the country to keep order, according to local press.

Protesters demanded universal healthcare, free and improved schooling and higher pensions.

The demonstration coincided with the constituent assembly elected to re-write the constitution beginning its work following a period of 100 days in which it set out its internal rules.

The current constitution was implemented during the Augusto Pinochet dictatorship (1973-90) and was one of the main targets of the 2019 protests.