Bosses at Universal Studios in Los Angeles are counting the cost of a huge fire.

The blaze broke out on a sound stage at the Hollywood site, which spans hundreds of acres and includes a theme park and a studio complex where movies and television shows are filmed.

As many as 50,000 tapes and reels were in the video vault but Universal Studios said there are duplicates stored in a different location.

The iconic courthouse square from Back to the Future was destroyed in the fire, and the famous clock tower that enabled Michael J Fox's character to travel through time was damaged, as was the King Kong exhibit.

Universal Studios spokesman Eliot Sekuler said a commercial shoot was taking place when the fire broke out.

The cause is under investigation and no initial damage estimates have been given.

More than 100 firefighters battling to bring the blaze under control. Three suffered minor injuries.

The fire will not affect the 2008 MTV Movie Awards, which is to be broadcast live Sunday night from the Gibson Amphitheatre in Universal City, according to the music network.

A major blaze erupted at Universal Studios in November 1990, destroying sets for several TV and movie productions, including Dick Tracy and The Sting and causing £12.5 million of damage.

© Independent Television News Limited 2008. All rights reserved.