Tucson Fire battled a blaze in the 5500 block of East Hawthorne Street, near Speedway and Craycroft, early Tuesday morning.
TFD arrived on the scene at about 4:25 a.m., according to a TFD social media post. Callers reported seeing smoke and flames in the area.
Crews arrived to find a fire in the guesthouse, that was being used for storage.
The house was difficult to access, TFD said, because of alley access and vehicles in the yard.
Flames spread to a shed across the alley. The fire was eventually extinguished. No injuries were reported.
The cause of the fire is under investigation, TFD said.