By EMILY SHAPIRO and ALEX STONE, ABC News

(IMPERIAL, Calif.) — At least 13 people have died from a crash between a big rig and an SUV in Southern California Tuesday morning, according to the California Highway Patrol.

A Ford Expedition SUV entered the intersection with the big rig and subsequently, the big rig, which was hauling two trailers, collided with the left side of the SUV before 6:15 a.m. local time, the highway patrol said.

Twenty-five people were in the Ford Expedition, ranging in age from 15 to 53, the highway patrol said.

Many passengers were ejected onto the road, the highway patrol said, adding that there were not enough seatbelts for 25 people.

California Highway Patrol Chief Omar Watson told ABC News that it’s “unfathomable” that 25 people were inside this one car. There was “major intrusive damage” to the vehicle, which only had a driver’s seat and front passenger seat, he said. It wasn’t clear why there weren’t any backseats, he said.

“What it indicates is that there’s not enough safety belts for the passengers, and we obviously want to make sure that everyone’s safely restrained within the vehicle,” Watson told reporters.

Twelve people, including the SUV driver, died at the scene, and another person from the vehicle died at a hospital, the highway patrol said.

The SUV driver was a 28-year-old man from Mexicali, Mexico, near the California border, Watson said.

More than 12 hours after the crash, authorities were working to identify the fatal victims to notify their families, he said.

The Mexican government issued a statement late Tuesday saying that so far the Mexican consulate has confirmed at least 10 of the dead were Mexican nationals. It also said authorities are still working to confirm the nationality of the other three people who died in the accident.

The highway patrol said the cause of the crash is not clear, adding that no law enforcement was involved in the incident.

There was no chase leading up to the crash, Watson said.

The only person in the big rig was the driver, a 69-year-old man from California, who sustained moderate injuries, the highway patrol said. Watson said he is in “bad shape” and has only given a partial statement to investigators so far.

Every survivor was injured to some extent, the highway patrol said. Multiple survivors were taken to area hospitals, hospital officials said.

Some patients suffered life-threatening head injuries, chest injuries and fractures, officials at El Centro Regional Medical Center said.

Several patients with minor injuries have since been released, Watson said during a briefing late Tuesday afternoon.

U.S. Immigration and Customs Enforcement confirmed in a statement that agents are conducting a human smuggling investigation and were on the scene of the fatal crash Tuesday.

“Special Agents from Homeland Security Investigations San Diego responded to the scene of today’s fatal crash in El Centro, California, and have initiated a human smuggling investigation,” ICE said in a statement. “The investigation is ongoing and no further details are available at this time.”

The crash was near Holtville in Imperial County, which is about 125 miles east of San Diego and about 10 miles from the Mexico border.

Imperial County Fire said 25 additional personnel were sent to the scene, including four to five additional ambulances and four air helicopters.

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