A welder doing work on a disco ball on the ceiling of the Amphitheatre nightclub in Ybor City sparked a fire that caused extensive damage.

According to Tampa Fire Rescue, the three-alarm fire broke out at the club, located at 1609 East 7th Avenue, just before 8 p.m. when welding sparks ignited material covering the ceiling.

The smoke and flames quickly spread in the two-story brick building. The automatic sprinkler system did operate but was not enough to completely extinguish the fire.

When firefighters arrived, smoke was pouring from the building and flames were seen coming from the roof. Three workers escaped the building and neighboring businesses were evacuated.

Twenty units and 50 firefighters responded to the fire.

Firefighters fought the flames for several hours before the building's roof gave way and collapsed, officials said. Two firefighters were injured and were taken to a local hospital for observation. They are expected to be okay.

The fire was brought under control by 1:30 a.m.

"There are multiple decks and ceilings within this old structure," said Tampa Fire Chief Tom Forward. "(That) made it very difficult for all of our firefighters, first of all, to be able to identify  the exact location of the fire."

Although damage was extensive, officials said the Amphitheatre remains structually sound. Officials said 7th Ave will remain closed in the immediate area due to cleanup.

The Fire Marshal's Office is investigating.