Crews with the Los Angeles Fire Department were battling a massive blaze in a three-story boarded-up commercial building in downtown Los Angeles.  

It was unclear how the fire in the 200 block of South Los Angeles Street broke out, but more than 135 firefighters were on scene to battle the blaze, the LAFD said in an alert.  

Video from Sky 5 showed heavy flames and smoke coming from the structure as firefighters were in defensive mode.  

Firefighters kept their distance, as there were concerns the building could collapse, LAFD officials said.

In addition to the primary building, the blaze jumped to a nearby five-story building, where one unit was ablaze. Authorities said with help from fire sprinklers, they were able to quickly extinguish that fire before it spread any further.

Crews will remain on scene “for an extended period” to ensure there are no smoldering sections in the burned-out structure.

The structure has been red-tagged by the city’s Department of Building and Safety. Nearby sidewalks will be closed to the public due to signs of compromised structural integrity.

LAFD officials also said that the building remains unsafe for crews to enter and that a “knockdown declaration” will likely be issued tomorrow morning.

No injuries were reported. The cause of the blaze is under investigation.