Thousands of Chileans have marched for human rights on the 40th anniversary of the coup that brought dictator Augusto Pinochet to power.
Some of the 60,000 carried pictures of their kin who were abducted or killed by the state and held signs with slogans such as "40 years after the coup, nobody and no one has been forgotten."
After a two-hour march, one group of hooded demonstrators set up barricades and squared off with police, some of whom were hit with stones and sticks. Police subdued the protesters with tear gas and water cannons.
The march ended at a cemetery with a memorial to the victims of Pinochet's Cold War regime.
"Forty years on, we are still demanding truth and justice. We won't rest until we find out what happened to our loved ones who were arrested and went missing" never to return, said Lorena Pizarro, leader of a relatives' rights group.
September 11 is the anniversary of the day in 1973 when air force planes bombed the presidential palace. Salvador Allende, an elected socialist president, committed suicide rather than be captured.
The governments that have ruled in the transition since Pinochet left power in 1990 have managed to reduce the South American country's poverty rate from 40 per cent to 14 per cent. But social disparities are stark.
Besides demands for social change, pressure is mounting in Chile to unmask the whole truth about a dictatorship that left more than 3,200 dead and some 38,000 people tortured.
Pinochet died in 2006 without ever having gone on trial.
