Two people died Monday after a big rig struck a car outside of Lancaster, forcing an hourslong closure of Highway 138, authorities said. The thoroughfare was reopened in both directions about 11:47 p.m.

California Highway Patrol officers and Los Angeles County Fire Department personnel responded to the crash site, near 60th Street West (map) in the unincorporated Antelope Valley, after the incident was reported by a caller at 6:49 p.m., a CHP spokesperson said.

One person died at the scene, according to the Fire Department.

A male juvenile was taken to a hospital in critical condition and pronounced dead shortly after 8 p.m., the CHP said.

The highway was temporarily shut down between 60th Street West and 50th Street West. A SigAlert was cancelled almost five hours after being issued.

The cause of the collision was under investigation.

Authorities originally said two people were critically injured, but later stated two died and a third party sustained no injuries.

Correction: An earlier version of this report erroneously indicated that the crash had occurred in Palmdale.

KLTA’s Ashley Soley-Cerro contributed to this report.