A downed power line added to the danger faced by Tucson firefighters early Thursday morning while battling a blaze that destroyed two buildings on the south side.

Fire crews arrived on the scene at about 1:30 a.m. and found two storage buildings in the 6000 block of South Nogales Highway engulfed in flames, Capt. Barrett Baker, spokesman for the Tucson Fire Department, said in a news release.

The fire was threatening a neighboring mobile home, and a downed power line nearby was arcing, posing an additional risk to firefighters.

It took nine units and 23 firefighters about 15 minutes to bring the blaze under control.

The origin and the cause of the fire are under investigation.