UNIVERSAL CITY, Calif. (AP) — A Los Angeles fire official says a large fire is burning on a lot at Universal Studios.

Los Angeles fire Capt. Frank Reynoso says the blaze was reported just before dawn Sunday on a sound stage on a back lot. There are no immediate reports of injuries.

Reynoso says filming could have been going on at the time and that there has been at least one explosion.

He says the fire is contained to the back lot, and firefighters are working to ensure the flames don't spread to nearby brush. Helicopters are dropping water onto the burning structures.

About 100 city and county firefighters are helping studio firefighters tackle the blaze.