Around 4 a.m., a house went up in flames on the 2400 block of Seybert Street in North Philadelphia.
The blaze claimed the life of one person and injured another.
1 dead, 1 injured in North Philadelphia house fire
"It's been a tough weekend for the fire department. This makes 40 or so fire fatalities this year," said Philadelphia Fire Captain Derek Bowmer.
Around 12:30 p.m., flames erupted on the 4700 block of Salem Street in Frankford. The fire rose to a second alarm before crews got it under control within an hour.
Five homes were damaged, and 20 people were displaced. Officials said no one was injured.
Neighbor Beverly Wilson called 911 and went over to help her elderly neighbor, who was rescued and stayed with Wilson until her family arrived.
"I'm glad that no life was lost," Wilson said.
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Neighbors say squatters have been known to stay in some of the vacant homes that were involved in the afternoon blaze.
Wilson said seeing people lose everything during the holidays is difficult.
"Northeast Baptist Church at 4744 Tackawanna Street will have their coat drive between 9 a.m. to 1 p.m. this Saturday or until supplies last," Wilson said. "We hate this during the holidays. A fire is always worse whenever it happens, but it seems more pronounced when it's the holidays."
Also on Monday, firefighters rescued two people from a home on the 300 block of Indiana Street.
And later in the evening, a house fire on North Lawrence Street in the city's Kensington section injured two people.
Philadelphia firefighters stayed busy overnight into Tuesday.
Investigators are working to determine if an early morning blaze in West Philadelphia is a case of arson.
Fire damages West Philly buildings
The fire damaged two vacant buildings on the 600 block of North Preston Street between Wallace Street and Haverford Avenue.
The fire burned for about an hour. The Fire Marshall deemed the incident an arson.
No injuries were reported.
If you need a smoke alarm, city fire officials urge any resident to contact 311 and it will be installed for free. Click here for more information.