Thirteen people killed in one of the deadliest US-Mexico border crashes on record have been linked to a migrant smuggling operation.
The dead were among 44 people who entered the United States through a hole cut into a border fence, according to Border Patrol.
The agency’s El Centro sector chief Gregory Bovino told the Associated Press surveillance video showed two vehicles driving through the fence early on Tuesday (US time).
A Ford Expedition and Chevrolet Suburban reportedly drove through an opening in the fence about 48 kilometres east of the crash, in the heart of California’s Imperial Valley, a major farming region.
The Chevrolet Suburban was carrying 19 people and caught fire soon after entering California.
All occupants escaped the burning vehicle and were taken into custody by Border Patrol agents.
The Ford Expedition crammed with 25 people continued on and was struck by a tractor-trailer a short time later.
Thirteen people were killed in the accident.
State highway patrol chief Omar Watson said 12 people were killed at the scene, about 18 kilometres north of the Mexico border, and another died after arriving at hospital.
It was unclear if the 4WD had stopped at a stop sign before crossing into the path of the truck, Mr Watson said.
He said numerous people were ejected from the vehicle during the crash.
The 4WD was a Ford Expedition that would typically seat eight to nine people legally and Mr Watson said it was “unfortunate” that so many people were in the car at the time.
Ten of the 13 people killed have been identified as Mexican citizens.
The rest of those in the SUV and the truck driver survived.
Police said they were not clear what caused the collision, but Border Patrol said its agents were not pursuing the vehicle before the crash.