An arson investigation has been initiated over a four-alarm fire that broke out at a Nob Hill apartment building on Saturday evening, bringing over 120 firefighters to the scene and injuring three residents.

At least three people were injured and a dog was reported missing after a four-alarm fire broke out at a multi-unit apartment building at Washington and Larkin Streets in Nob Hill on Saturday evening at around 5:52 p.m., according to CBS News. Over 120 firefighters were called to fight the blaze, which was extinguished by 8:30 p.m. Crews were expected to remain on the scene for several hours.

The San Francisco Fire Department said on X that the fire spread throughout all three floors of the building, extending to the roof, and adjacent buildings were also damaged. A person in a wheelchair was pulled from the building, and two people required assistance down the stairs.

One resident was reportedly taken to the hospital, and others were treated at the scene.

It wasn’t clear how many people were displaced or what caused the fire. According to KRON4, an arson investigation has been initiated.

Image via Citizen app