At least one semi and nearly 20 cars collided on a freeway in Agua Dulce, CA, in the mountains north of Los Angeles, leaving at least 17 people injured, including two critically, according to a report in The Republic.

Los Angeles County fire Capt. Mark Savage said the vehicles, including one or two big rigs, tangled early Tuesday morning on the southbound side of State Route 14 — known locally as the Antelope Valley Freeway —  midway between the high desert Antelope Valley and the Los Angeles Basin. The highway travels through the San Gabriel Mountains that rises to a summit elevation topping 3,200 ft.

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.

The crash was reported at 9:45 a.m. and resulted in the closure of all the southbound lanes and two northbound lanes of the freeway. The road was completely reopened at 2:08 p.m., according to the California Highway Patrol.

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 is under investigation.