A three-car crash triggered by a driver illegally passing cars on the shoulder resulted in the deaths of six people and the hospitalization of four others in Riverside County on Monday.

Shortly before 2:30 p.m., Cal Fire and the Riverside County Fire Department crews responded to a three-car collision that started a small fire on Gilman Springs Road and Bridge Street in Lakeview, according to Cal Fire officials.

When responding officers arrived, the cars were all ablaze, Cal Fire officials stated. Ignited by the collision, the fire spread to nearby vegetation and burned more than 3.5 acres.

Initially officials declared four people died on the scene. Two hours later officials announced that six people had died.

Four other victims were taken to a nearby hospital with minor to serious injuries.

The identities of the deceased and injured victims had not been released as of Tuesday morning.

The crash was caused by a driver who tried to pass on the right shoulder but ran out of room, then hit the guard rail and swerved head-on into traffic, California Highway Patrol Sgt. Adrian Horta told KTLA5.

The driver of that vehicle died, and the passenger in the car’s front seat was extricated from the car and taken to the hospital, KTLA5 reported.

One vehicle involved in the incident was pushed off the road and into a field where it caught fire, killing three passengers. No details were available Tuesday morning on the other two deaths.