Massive 3-alarm fire engulfs industrial building in SoCal

COMMERCE, Calif. -- A massive fire erupted Friday morning at a commercial building in Los Angeles County, prompting a response from more than 100 firefighters who attacked the blaze from all sides of the structure.

The three-alarm blaze began shortly before 4 a.m. at a structure measuring 350 feet by 350 feet in Commerce, California, according to the Los Angeles County Fire Department. The roof quickly collapsed.

No injuries were immediately reported. Whether anyone was inside the structure when the fire began was unclear.

Firefighters were using aerial ladders to attack the flames from all sides of the building.

The cause of the fire is unknown.

DEVELOPING: More details will be added to this report as they become available.