A three-alarm fire broke out late Wednesday night at the Williamsport Manor, 450 Center St., forcing the evacuation of the apartment building’s nearly 100 residents.

There were no reports of any fire injuries, but a few residents were treated at the scene for heat exhaustion or medical-related issues.

Many of the residents are elderly or have to cope with minor medical problems or disabilities.

The fire erupted in a kitchen in an apartment on the fifth floor, the top floor, about 9:15 p.m., fire officials said.

The fire triggered both the building’s fire alarm and sprinkler systems.

A team of city police officers helped more than a half a dozen residents down flights of stairs.

“The fifth floor was starting to fill up with smoke,” one officer said.

The second and third alarm brought additional firefighters and ambulances from South Williamsport, Old Lycoming Township and Montoursville.

The fire was confined to the one apartment, but two apartments on the fourth floor sustained some water damage.

The majority of residents were expected to be allowed back in their apartments by the end of the night, for officials said.