Two people, including at least one child, on an electric bike were seriously injured after colliding with a car in San Marcos on Monday evening, officials said.

The crash happened on South Santa Fe Avenue near North Las Flores Drive just before 6:30 p.m.

Both riders were on the same e-bike and sustained non-life-threatening injuries, according to the San Diego County Sheriff’s Department. Officials said one victim was airlifted, while the other was taken by ground ambulance. Neither rider was wearing a helmet at the time of the incident, deputies said.

One of the drivers involved, who wished not to be identified, told NBC 7 that the e-bike riders turned at the red light — when southbound vehicles had the green light — and collided with the vehicle behind her. One of the victims went under that vehicle, and the other went over it and bounced off her van, the driver said.

SDSO said that all other parties involved stayed at the scene.

It’s unclear what caused the crash or who was at fault, but alcohol and drugs were not believed to be factors in the collision.

This is a developing story that will be updated as more information arrives.