SAN DIEGO — A major crash near the San Diego Safari Park Tuesday evening left at least six people injured, San Diego Fire-Rescue said — four of which remain in critical condition.

The crash was reported as a vehicle rescue around 4:08 p.m. in the 15000 block of the San Pasqual Valley Road, according to SDFD. A total of 55 personnel were assigned to the scene, as well as a helicopter and multiple rescue vehicles.

Crews arrived to find two severely damaged vehicles, a pick-up truck and a sedan, after they collided in the eastbound lanes of San Pasqual Valley Road.

SkyFOX footage of the scene showed dozens of firefighters and other personnel around the vehicles as they worked to extricate people that were trapped inside them as a result of the crash.

According to SDFD, a total of six patients were then transported to the hospital following the crash. Four sustained injuries described by fire officials as life-threatening. The extent of the injuries for the other two patients is not known at this time.

Road closures were in place surrounding the site of the crash for the rescue and clean-up of debris. They have since been reopened.

The cause of the crash remains under investigation by authorities.

This is a developing story. Check back for updates.