By CBSLA Staff

HOLLYWOOD (CBSLA) — Fire crews were battling a greater alarm blaze at a commercial structure Monday night.

According to the Los Angeles Fire Department, there were 84 firefighters responding to the vacant building as of 9:10 p.m. where flames had spread from the original unit through the attic.

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Crews initially responded to the fire in the 7400 block of West Sunset Boulevard, near Gardner Street, at about 8:45 p.m., according to the department.

When crews arrived on scene, flames were already exploding through the roof of the structure, forcing the firefighters to take a defensive position outside of the structure.

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The full extent of the fire was still unknown as fire crews applied large hose streams from the exterior of the structure.

The blaze was officially declared a knockdown at about 9:22 p.m. with 84 firefighters on scene. According to LAFD, gas lines were reportedly feeding the blaze until crews were able to shut off utilities to the structure.

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There were no injuries, and the cause of the fire was still under investigation.