SAN DIEGO (KGTV) -- Firefighters have been working overnight to contain a large fire that engulfed an abandoned commercial building in Mission Valley, previously home to the country western bar, "In Cahoots."

The fire began around 1:38 a.m. Saturday in the 5300 block of Mission Center Road, and more than 60 firefighters were dispatched to the scene.

Due to safety concerns, fire officials said they were taking a defensive approach. They kept personnel outside the building while using drones and infrared technology to fight the fire from a distance.

Officials have closed Mission Center Road in both directions near the site, which is close to a busy area near Food 4 Less and Chick-fil-A.

The battalion chief on scene said that the building's roof collapsed around 8 a.m.

The building, which has been boarded up since the bar closed several years ago, will likely remain an active fire site throughout Saturday,

The cause of the blaze remains unknown. Check back with ABC 10News for updates on this developing story.