Nine people were injured at the Irvine Meadows Amphitheatre after an elderly man struck a fence and several pedestrians with his car,  but investigators said drugs or alcohol were not a factor.

Irvine police and the Orange County Fire Authority responded to a single vehicle collision around 6:45 p.m. on Saturday. An older man was driving through the parking lot of the amphitheater when he hit a fence near the front entrance, according to police.

After striking the fence, the driver hit another car and numerous pedestrians before hitting an unoccupied, parked police car and coming to a stop.

The force of the collision pushed the police car into a grassy area near the box office, where several people were picnicking before a concert. The police car struck numerous individuals before coming to a stop.

Nine people were treated and five were transported to the local hospital, according to police. Four of those five were treated for major trauma and one was treated for minor injuries.

The cause of the accident was unknown.

Drugs or alcohol were not believed to be a contributing factor in the crash, police said.

Anyone with information about the collision is asked to call Detective Jon Cherney at 949-724-7024.