El CENTRO, Calif. >> An SUV packed with 25 people pulled in front of an oncoming tractor-trailer on a two-lane highway cutting through farmland near the Mexican border early today, killing 13 and leaving bodies strewn across the roadway.

When police arrived some of the passengers were trying to crawl out of the crumpled 1997 Ford Expedition, the front end of the rig still pushing into its left side and two empty trailers jackknifed behind it. Other victims were wandering around the fields.

Twelve people were found dead when first responders reached the highway, which winds through fields in the agricultural southeastern corner of California about 125 miles (201 kilometers) east of San Diego. Another person died at a hospital, California Highway Patrol Chief Omar Watson said.

“It was a pretty chaotic scene,” Watson said, who also described it as “a very sad situation.”

The injuries ranged from minor to severe and included fractures and head trauma. Six people were being treated at El Centro Regional Medical Center. Four were flown to Desert Regional Medical Center in Palm Springs, where one person is in critical condition and the others were stable, spokesman Todd Burke said.

The 22-year-old driver of the Ford Expedition was from Mexicali, Mexico, and was killed. The 69-year-old driver of the big rig, who is from nearby El Centro, was hospitalized with moderate injuries.

The crash occurred around 6:15 a.m. at an intersection just outside the agricultural community of Holtville, which dubs itself the world’s carrot capital.

Authorities said the tractor-trailer and its two empty containers were northbound on State Highway 115 when the SUV pulled in front of it from Norrish Road. It’s not clear if the SUV ran a stop sign or had stopped before entering the highway. It’s not yet known how fast the tractor-trailer was traveling.

The deceased ranged in age from 20 to to 55. Among the injured, the youngest is 16 years old.

The investigation will look into why so many people were crammed into the 1997 Ford Expedition, a vehicle built to hold only about eight people safely.

“Obviously, that vehicle is not meant for that many people,” Watson said. “It’s unfortunate that that many people were put into that vehicle because there’s not enough safety constraints to safely keep those people in that vehicle.”

The speed limit for tractor-trailers on the highway is 55 mph (88.5 kph), according to CHP Officer Jake Sanchez. The other road is also 55 mph for vehicles.

A 1997 Ford Expedition can carry a maximum payload of 2,000 pounds. If it had 25 people inside, that would exceed the payload limit — which would tax the brakes and make it tougher to steer, said Frank Borris, former head of the U.S. National Highway Traffic Safety Administration’s Office of Defects Investigation.

“You’re going to have extended stopping distances, delayed reactions to steering inputs and potential over-reaction to any type of high-speed lane change,” said Borris, who now runs a safety consulting business.

SUVs of that age tended to be top-heavy even without carrying a lot of weight, Borris said.

“With all of that payload above the vehicle’s center of gravity, it’s going to make it even more unstable,” he said.

Officials were still working on identifying the dead and said they did not know if the SUV was carrying farm workers or migrants crossing into the country illegally. The Mexican consulate was assisting since so many people in the region live and work on both sides of the border.

The harvest of lettuce and other winter vegetable crops runs from November until March, when buses and SUV carrying farmworkers are often rumbling down the rural roads to the fields in the early morning hours.

The area has also seen smugglers carrying in migrants in trucks and vehicles. Hundreds of migrants who died after crossing the border are buried in unmarked graves in Holtville’s cemetery on the edge of town.

The crash occurred amid verdant farms that grow a wide variety of vegetables and alfalfa used for cattle feed. Hours after the accident, a crew of a few dozen worked the fields near the scene.

Macario Mora, a spokesman for Customs and Border Protection in Yuma and El Centro, said the Border Patrol was helping other law enforcement with the crash. He said the immigration status of those in the SUV was unknown and being investigated.

“It was an unusual number of people in an SUV, but we don’t know who they were,” Mora said, adding that they could have been farmworkers.