Firefighters are battling a fire that began in a vacant building in northwest Fresno on Friday night, said Fresno fire Battalion Chief Todd Tuggle.
Flames engulfed the building on Shaw Avenue between Hayes and Bryan avenues around 7 p.m., and a second alarm was called.
Firefighters were worried about power lines falling, Tuggle said.
A home nearby was threatened, but firefighters were able to keep the flames away.
Tuggle said the fire may have been caused by homeless people who were inside the building at the time, but the exact cause is still unknown.
Shaw between Hayes and Bryan is closed and the fire department expects to be on the scene until 11 p.m.
This story will be updated.