A light rail train collided with an ambulance Saturday in downtown Denver, injuring at least six people and sending a train car through a storefront window, police said.

Three light rail cars derailed when the ambulance and train collided near the Colorado Convention Center around 4:30 p.m., police spokeswoman Det. Virginia Lopez said.

Denver Health Paramedics said the ambulance had its emergency lights and sirens on.

Two paramedics were temporarily trapped inside the ambulance. Both paramedics and a passenger in the ambulance were injured, along with a person in a separate vehicle damaged by the collision, Lopez said.

Paramedic James Sullivan, 47, and Denver Health Paramedic School student John Gubernick were both in fair condition with bruises, Denver Health Medical Center officials said.

Another person was in good condition and a fourth person was treated and released from the hospital. Three other people were taken to nearby Exempla St. Joseph Hospital, Denver Health spokeswoman Lynn Ercolani said. Their conditions were not released.

''None of the injuries appears to be life threatening,'' Lopez said.

One light rail car crashed into the atrium of a Wolf Camera store but no one was injured, Lopez said. The ambulance sustained serious damage after crashing into another building. Four other vehicles also were damaged.

It wasn't immediately clear who was at fault in the accident.