Three men and a woman died in a fiery head-on collision near Lake Mathews in Riverside County early Saturday morning, authorities said.
At around 5:10 a.m., a 2001 GMC Sierra driving westbound on Cajalco Road , east of Gavlan Road, collided with a 2006 Chevrolet Avalanche driving eastbound on the same road, California Highway Patrol said in a written statement.
The Chevrolet immediately caught fire upon impact and became engulfed in flames. Both male passengers were pronounced dead at the scene, CHP said.
The GMC vehicle's driver, a 56-year-old man from Perris, was also pronounced dead at scene, according to authorities.
A 52-year-old female passenger, also from Perris, suffered "major injury" and was transported to a nearby hospital where she died, according to CHP.
No other passengers or victims were reported in either of the vehicles.
CHP was investigating the crash.
It is unclear what led to the head-on collision.
Anyone with information was asked to contact California Highway Patrol's accident investigation unit at 951-637-8000.
KTLA's Derrick Clemons contributed to this report.