SANTA CLARITA, Calif. -- A big-rig truck and nearly 20 cars collided Tuesday on a freeway in the mountains north of Los Angeles, leaving at least 17 people injured, including two critically, authorities said.

Television news footage showed more than a half-dozen cars, pickup trucks and SUVs crumpled together and piled on top of each other in a cluster of wreckage on the southbound side of state Route 14 in Agua Dulce. The route is known locally as the Antelope Valley Freeway, where cars heading from the high-desert bedroom communities often speed on their way to the Los Angeles basin.

The crash was reported at 9:45 a.m., and Los Angeles County fire Capt. Mark Savage said "there are 19 vehicles involved, at least one or two big-rigs."

All the southbound lanes and two northbound lanes were reopened at 2:08 p.m., according to the California Highway Patrol.

There was no fire and no hazardous material spills, Savage said.

Firefighters freed a person trapped in the wreckage, and a fleet of ambulances ferried the injured to hospitals, Savage said. Fire Capt. Doug LaCount told KABC-TV that most of the injuries were minor.

The cause of the accident was under investigation.

The highway through the San Gabriel Mountains rises to a summit elevation topping 3,200 feet.

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  • This image made from video provided by KABC-TV shows fire officials working on a freeway pileup in northern Los Angeles County involving at least 19 vehicles that has injured at least 15 people, two of them critically. Los Angeles County fire Capt. Mark Savage says the vehicles, including one or two big-rig trucks, tangled early Tuesday morning on the southbound side of State Route 14 midway between the high desert Antelope Valley and the Los Angeles Basin. (AP Photo/KABC-TV)

  • Firefighting paramedics remove an injured motorist after an accident, Tuesday, June 26, 2012 at the site of a freeway pileup in northern Los Angeles County involving at least 19 vehicles and left at least 15 people injured, two of them critically. (AP Photo/Rick McClure)

  • Firefighting paramedics remove an injured motorist after an accident Tuesday June 26, 2012 at the site of a freeway pileup in northern Los Angeles County. (AP Photo/Rick McClure)

  • Firefighting paramedics assist an injured motorist after an accident Tuesday June 26, 2012 at the site of a freeway pileup in northern Los Angeles County. (AP Photo/Rick McClure)