LOS ANGELES (AP) — Officials say 150 firefighters battled a huge blaze that gutted a commercial building in downtown Los Angeles.

The fire broke out around 2 a.m. Tuesday in a three-story building at the corner of Third and Los Angeles streets. There were several small explosions from inside as flames erupted through windows and sent up an enormous plume of dark smoke.

Crews kept the flames from spreading to neighboring structures and had the fire under control within about three hours. There were no injuries reported.

The building, which housed several small businesses, was declared unsafe to enter. The cause of the fire is under investigation.