CHICAGO – A Chicago firefighter is in serious condition after falling from a roof during a call in the city Northwest Side, according to officials.

The incident happened around 6:10 p.m. Sunday in the 800 block of North Hamlin Boulevard in Humboldt Park.

According to the Chicago Fire Department, firefighters were initially notified that several people were trapped inside a three-story building on fire.

When the teams arrived at the scene, they found that heavy flames on the second floor had spread to the third floor and began to intervene in the fire from the outside.

More than 100 fire crews responded to the scene. Once the fire was somewhat under control, intervention started from inside the building.

The teams also started to search for the trapped victims. After an extensive search, they found that no one was trapped and many people self-evacuated.

About 10 minutes after the call, a firefighter working on the roof lost his balance while responding and fell through a light shaft and into the basement, according to CFD.

The seriously injured person was taken to Stroger Hospital by ambulance. His identity and age were not disclosed.

CFD said at least eight people were displaced as a result of the fire.

The cause and cause of the fire are still under investigation.

This is a developing story and updates will be provided as they become available.