SUMMIT, Ill. (CBS) — A mother, father and two small children were rescued, but a firefighter was left injured, in an extra-alarm fire overnight in southwest suburban Summit.

Firefighters were called to the blaze in the 7300 block of West 61st Street about 11:45 p.m., according to a Summit Assistant Fire Chief Rich Gallaga.

The fire burned three houses — a single-family home and two 2 1/2-story apartment buildings. A third alarm was raised before the fire was extinguished about 3 a.m. Thursday, Gallaga said.

The blaze began in the rear of the home at 7320 W 61st St. before spreading to the two residences on either side — 7322 W. 61st St. and 7318 W. 61st St., according to Gallaga.

A firefighter suffered a mild concussion when debris fell on him while he was in a gangway between two of the buildings, Gallaga said. The firefighter was taken to MacNeal Hospital in Berwyn.

He was released and was resting at home Thursday morning, according to Gallaga.

Firefighters had to force their way into the top-floor unit at 7322 W. 61st St. to rescue a family of four from the flames, Gallaga said.

All four — a mother, father and their two small children — were asleep in a bedroom when firefighters forced their way into the apartment, Gallaga said.

The other residents of the three buildings escaped the blaze under their own power, Gallaga said. The fire displaced five families and a total of 28 people.

A pregnant woman complained of back pain and was treated at the scene, according to Gallaga.

The American Red Cross said in a message on its official Twitter feed that a team from the organization is headed to the blaze to provide for emergency needs.

The cause of the fire remained under investigation, but was not considered suspicious Thursday morning, according to Gallaga.

The Sun-Times Media Wire contributed to this report.

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