READING — A massive fire tore through the Old Reading Schoolhouse Condos, displacing more than 60 residents and sending one firefighter to a hospital with minor injuries, officials said.

Up to seven alarms were struck, and more than 100 firefighters were needed to fight the smoky blaze that broke out just before 1:15 p.m. at the four-story, red-brick building on Sanborn Street, Fire Chief Gregory Burns said. Smoke continued to waft from the roof of the turn-of-the-century schoolhouse that was converted to condos in the 1980s. Burns said firefighters encountered smoky conditions on the fourth floor when they arrived, and the fire quickly spread.

“It was burning up into the slanted portion of the roof and traveling very quickly,’’ he said. Firefighters from several communities including Boston, Lynn, Lynnfield, Woburn, Wilmington, Everett, Medford, and Somerville provided assistance, according to Burns.

“This is a significant fire,’’ he said at the scene.

Burns said roughly 60 people were home when the fire broke out in the 41-unit building. Most got out on their own, but firefighters had to help some elderly people to safety. In addition, Burns said, a number of pets were rescued.

No civilian injuries were reported.

Burns said one firefighter who suffered minor heat-related injuries was taken to an area hospital as a precaution.

No residents were allowed to return to their units Thursday night.

Melanie Murphy, who lives on the first floor, was among the residents forced to evacuate. She hugged a friend outside the building as the fire continued to rage in the early afternoon.

Susan and Jim Cotter, both 59, who moved into their fourth-floor unit about six months ago, said they were both at work when the fire started. But their 14-year-old cat, Luna, was in their unit and remained unaccounted for Thursday evening. “It’s just such a beautiful old building,’’ Susan Cotter said. “It’s just such a shame. . . . It’s a little surreal right now.’’

Jim Cotter said their daughter, who is vacationing in Italy, contacted him when she heard the news through social media. She initially texted “fire?’’ and then called him. “She’s crying,’’ he said.

The Cotters said they planned to stay with family Thursday night. In addition, they said, friends had also reached out to offer help. “It’s a nice community,’’ Susan Cotter said. “There’s always a lot of support.’’

Jim Davis of the Globe Staff and correspondent Maddie Kilgannon contributed to this report. Travis Andersen can be reached at Travis. Andersen@globe.com Follow him on Twitter @TAGlobe.