SAN FRANCISCO (KRON) — Two San Francisco firefighters were hospitalized Wednesday morning after sustaining injuries while responding to a large three-alarm house fire in the Marina District, according to the San Francisco Fire Department.

Approximately 145 firefighters battled the blaze at the three-story home in the 2500 block of Chestnut Street, fire officials said. The fire has been contained and is under control as of 6 a.m.

Earlier Wednesday morning at 4:15 a.m., arriving firefighters saw heavy fire from the second floor of the building. Those flames were initially extinguished, but the fire had spread to the third floor and to the three-story building to the left, according to SF Fire Chief Dean Crispen.

Two firefighters were injured in the response and rushed to an area hospital. The two firefighters fell through the third floor to the second floor, Crispen said. The extent of injuries sustained is unknown. According to the fire chief, they are both in stable condition.

Residents of both buildings were evacuated, Crispen said, and officials are working to relocate them.

The building where the fire started was undergoing some level of construction, Crispen said, which may have allowed the fire to spread across floors with more ease.

An arson unit responded to the scene to determine the cause of the fire and its origin.

Authorities are advising the public to avoid the area of Chestnut Street between Baker and Broderick streets due to the fire activity.

This is a developing story. Check back for updates.