*UPDATE* 10/24 1:15 a.m. – Portland officials on Monday afternoon said the cause of Saturday's fire was improper disposal of smoking materials.

The city says "it's important to make sure that citizens follow smoking safety tips and ensure that materials are put out by using a deep, sturdy ashtray that is placed away from anything that can burn."

Learn more fire safety tips here: http://portlandmaine.gov/fire

PORTLAND, Maine (NEWS CENTER)-- A Portland firefighter was injured Saturday morning while responding to a house fire at 79 Lincoln Street in the city.

Portland Fire Department Deputy Fire Chief Robert Stewart says the firefighter slipped and injured his knee, and take to a nearby hospital for treatment.

The Portland Fire Department was notified of a fire at 79 Lincoln Street around 9:30 Saturday morning. The building two story residential building was heavily damaged by flames with the worst of that damage on the second floor. According to Stewart, only the female homeowner was at the house, but not inside, at the time the fire started. Two tenants who live on the second floor were away from the home, reportedly at a wedding according to neighbors.

Neighbors said the woman who owned the house had only been there for about a year and had "put so much work" into the house that used to be "not very nice."

Investigator are working to pinpoint a cause of the fire, currently it is unknown where it started. Stewart said he did not believe the home to be a total loss, but an inspector will have the final say.

Two of the buildings surrounding the home sustained minor damage to the sidings.

At the time he was interviewed, around 11:30am, Stewart said there was no sign of the two cats neighbors said resided in the building.