18 rescued in overnight apartment fire in San Francisco's Alamo Square

Firefighters in San Francisco rescued more than a dozen people from a burning apartment building after a fire broke out in the city's Alamo Square neighborhood early Thursday morning.

Shortly before 2 a.m., the fire department was called to the 800 block of Fillmore Street, near Grove Street. When the first fire crews arrived, they found a three-story building with heavy fire from the second story and occupants who were trapped, prompting a second alarm.

Using ground and aerial ladders, firefighters performed multiple rescues. A total of 18 people were rescued from the second and third floors of the building, according to firefighters.

One person was injured but is expected to recover, the fire department said.

The fire spread to the third floor of the building and was isolated to two structures. Shortly before 4 a.m., firefighters said the fire was under control.

"Our members did an outstanding job, I like to commend all of them," Chief Dean Crispen said in a video posted on social media.

The American Red Cross was dispatched to the scene to assist residents. The number of displaced residents was being assessed.

Firefighters are expected to remain on scene for the next several hours for investigation. The cause of the fire was not immediately known.