MEDFORD — Four people, including a police officer, are hospitalized following a fire that broke out Tuesday in the first floor of a multi-unit apartment complex in Medford.

The fire was reported at about 5:20 p.m. at a four-unit apartment complex on Division Street, police said.

Three people were inside the building when the blaze broke out, including one woman who was trapped on the second floor. All three residents were taken to a local hospital for smoke-related injuries, as was a Medford Police officer, authorities said.

The building was heavily damaged by the fire, which was extinguished in less than an hour.

The cause of the blaze has not yet been determined.