A teenager shot at a crowd with a pellet gun on Monday in the Chilean port city of Valparaiso and injured six people, state television said.

State TV says the unidentified 15-year-old gunman fired in downtown Valparaiso several times before he was brought down by passersby. TV originally reported seven injured but downgraded the number of victims following a hospital report.

Valparaiso Mayor Jorge Castro said a fight broke out earlier in the area and the shooting could be related.

"It's presumed that this is the result of a fight between two groups who have already been at odds," Castro said.

Valparaiso police Chief Fernando Bywaters told local television that two people have been arrested and one of them is 15. Reporters at the scene reported blood stains outside of Chile's Congress building near the scene of the shooting.

The injured are being treated for pellet wounds at Valparaiso's Carlos Van Buren hospital and police are investigating.