The lives of none of the victims were in danger, tweeted Karla Rubilar, the top government representative in the region.
The reason for the explosion was not known.
“Now we are on the ground coordinating emergency efforts and police are working to clarify what happened,’’ Rubilar tweeted.
Deliberate explosions are rare in the South American country.
In September 2014, a bomb attributed to an anarchist group injured 14 people in Santiago de Chile.