IMPERIAL COUNTY, California - A Tuesday (March 2) morning crash involving a big rig in Imperial County, California has resulted in multiple deaths, authorities say.

According to CNN, California Highway Patrol Officer Arturo Platero says that at least 12 people were killed after a vehicle that was reportedly traveling westbound on Norrish Road near State Route 115 collided with a big rig truck that was traveling northbound on the 115.

Imperial County Fire officials said multiple agencies were responding to the crash, which is being treated as a mass casualty event, CNN reports.

Police say the exact cause of the incident is still under investigation. 

The site of the crash is in southeastern California, about 10 miles east of El Centro and nearly 10 miles north of the Mexican border.