LEMON GROVE, Calif. -- A motorcyclist died when he hit a curb and flew off his bike in Lemon Grove, a sheriff's official said Saturday.

Witnesses saw the motorcyclist lose control and hit the curb at the intersection of La Corta Street and Massachusetts Avenue around 9:50 p.m. Friday, said San Diego sheriff's Lt. Hope Andrews.

The motorcyclist was taken to Scripps Mercy Hospital in Chula Vista, where he was pronounced dead two hours later, she said.

Andrews said the investigation is ongoing, and she didn't know if alcohol was a factor in the accident.

The motorcyclist's age was not immediately known. His name has not been released pending family notification.