Authorities say two men are dead after a helicopter crashed near a Northern California freeway, knocking power lines into traffic lanes and starting a grass fire near the road.

California Highway Patrol Officer Aaron Quistad says the helicopter crashed early Friday on Interstate 680 near Fremont. Officials with the patrol and the fire department are on the scene and have closed one lane of the freeway.

Coroner's officials say they received word of two male victims but did not yet know their identities.

Quistad says he does not know who owns the helicopter but that it does not belong to law enforcement.

Fremont is in Alameda County, about 30 miles south of Oakland.