CARNEGIE, Pa. -- Intense flames attack two apartment buildings overnight in Carnegie.

The roof of one of those has collapsed, and now the walls are in danger of coming down. Flames were roaring out of the windows of two apartment buildings and threatening a third apartment building and three houses in the 400 block of Third Avenue.

Officials said the fire started in a sleeping room on the second floor.

Initially, three people were trapped in one of the apartment buildings, but firefighters used ladders to get them out. Police knocked on doors in the entire block, telling residents to get out immediately. There were no serious injuries, but the flames and smoke were very thick.

It took 50 firefighters from Carnegie and four surrounding communities about an hour and a half to contain the fire to three buildings. Some people wanted to go back and get possessions, but couldn't.

Fire victim Monica Martons said, "I did want to go back, but the officer kept telling me get out of here, you can't go in there, you know cause I wanted to get a few things.”

The high temperatures, flames, and smokes affected residents and firefighters. Three residents and three firefighters are being treated for smoke inhalation and injuries suffered in that fire. Investigators don't know how it started. The county fire marshal is on the scene.