FRESNO, Calif. (KSEE/KGPE)- Fresno City Fire crews spent several hours putting out a five-alarm blaze Saturday night, and saving both people and pets from the flames.

Fire crews say the residential structure fire was reported at Belmont Avenue and Broadway Street around 10:45 p.m. and it was immediately determined to need a three-alarm response.

Firefighters say the smoke was heavy and thick in the building upon their arrival and their first response was to aggressively search for anyone inside.  Two people were rescued from the building, as well as several animals, including cats and a bearded dragon.  The two people were taken to an area hospital for treatment for the multiple burns they received.

The building is a three-story apartment, with a basement and an attic, and fire personnel say fire stretched upwards from the basement, engulfed all three floors, and climbed into the attic.

As fire began to rapidly spread throughout the building via a mechanical chase, and the roof began to cave in, the need for resources was elevated to a 5-alarm response.

Battalion Chief Brian Price says that at the peak of the firefight there were 70 firefighters battling this blaze, which was over two-thirds of the resources the department has on in an entire day, so additional resources were called in to be able to allow the fire department to respond to other calls in the city.

Price praises the residents who were able to close their doors to keep smoke and fire out of their units; by doing so he says they were able to keep themselves and their pets safe.

Firefighters say the building is currently uninhabitable due to the gas and power being turned off.  The Red Cross was called in to assist displaced residents.

Investigators say they believe they have identified the area of the building where the fire originated, but the cause of the fire is still under investigation.

Fire personnel say the building is severely damaged to the point it may need to be demolished, and that decision will have to be made in the upcoming days.