Violent protests have broken out in Chile as President Michelle Bachelet presents a state-of-the-nation report to Congress.

One man has reportedly died of asphyxiation after masked demonstrators burned a pharmacy and a supermarket in downtown Valparaiso, which is where the South American nation's congress meets.

Local TV broadcast images of smoke rising from different parts of the city. Government spokesman Marcelo Diaz condemned the man's death in comments to TVN television.

The protest began as a peaceful march but turned rough as some demonstrators threw rocks at police and gasoline bombs at buildings. Officers responded with tear gas and high-pressure blasts of water.

Bachelet emphasized achievements such as a reform guaranteeing free education in her speech Saturday. She called it a process from which "there is no turning back."