LEOMINSTER - Up to a dozen people were displaced by a fire on the top floor of a three-decker on a freezing Saturday night. The cause of the blaze remains under investigation.

Leominster firefighters responded Saturday evening to a report of a fire at 125 5th St., Leominster Deputy Chief Scott Cordio said Sunday. The call went to a second alarm.

“It burned the third floor and burned some of the siding on the exterior, but there was water damage on all floors,” said Chief Cordio.

The flames rekindled around 2 a.m. Sunday, prompting firefighters to return to the scene to extinguish a few pockets of flames in the walls, Chief Cordio said. Companies cleared the scene by 4 a.m. Sunday and fire detail left the scene by 8 a.m.

There were no injuries reported. Investigators from Leominster and state police are seeking a cause.

Chief Cordio said two families requested housing assistance from the American Red Cross, while the third family in the building planned to stay with friends.  He estimated that 12 people were displaced by the blaze.

Firefighters also battled cold temperatures in addition to the flames, but were doing well warming up.

“It was cold, but when you’re out and actually working, it’s not too bad,” Chief Cordio said. “Everyone came back and is doing pretty well.”