A commuter train and a truck have collided, causing three carriages to derail northwest of Los Angeles.

Police in Oxnard, California, say the crash was first reported at 05:44 local time (13:44 GMT).
A helicopter from a local television station showed emergency responders treating multiple people.
A spokesman for the Ventura County Fire Department told the BBC that it is believed no one had died in the accident.
Captain Mike Lindbery said the train was carrying 51 passengers, and 28 of those were transported to several local hospitals.
The driver of the truck that collided with the train fled the scene, and was "taken into custody south of the scene less than a mile," Capt Lindbery said.
The locomotive had a camera on the lead carriage, footage from which will be used in the investigation.
The National Transportation Safety Board (NTSB), the agency that leads transport investigations for the US government, said in a tweet, "NTSB launching team to rail accident in Oxnard, CA. More details to come."

Aerial footage from the scene shows multiple emergency vehicles at the scene, with several fire fighters and paramedics moving people into ambulances.
One carriage can be seen overturned and laying partially in a nearby highway. Two others were overturned laying parallel to each other, and a fourth remains upright.
In a nearby intersection, the burnt-out shell of a truck can be seen with remnants of fire extinguishing foam.
The train was destined for Los Angeles, and crashed about 65 miles (100 kilometres) away from its destination.
A Metrolink train collided with a freight train in 2008 in another part of southern California, killing 25 people and injuring more.