More than two dozen people were displaced by an apartment fire Sunday in the Tenderloin, according to the San Francisco Fire Department.

The blaze likely was caused by a cigarette dropped into a lightwell, fire officials said.

The inferno at the six-story, 40-unit apartment building at 347 Eddy St. was reported just after 8 a.m., a dispatcher said. It was brought under control at about 10:30 a.m.

The blaze left 25 people, including two children, without homes, the dispatcher said.

One person was reportedly injured in the fire, though the extent of the injuries was not immediately known.

The American Red Cross was setting up a shelter Sunday afternoon at a nearby church, spokeswoman Kathleen Maclay said.