Hundreds of people were drawn to the area of Sturgis and Fulton streets, watching as flames licked the back side of one home and clouds of smoke filled the area.
Fort Wayne Fire Department spokeswoman Stacey Fleming said she couldn't comment on the cause or provide any other information until the fire was under control.
Witnesses at the scene said the fire started at one home at about 7 p.m. By nearly 10 p.m. at least four houses in total were affected, and fire crews were still battling the blaze.
Firefighters took turns working, while paramedics stood by to assist them as they came out of the home. Some stripped off their gear, revealing shirts soaked in sweat. Coolers filled with Gatorade and water were available at the scene.
At about 10 p.m. the temperature outside was close to 90 degrees.
Traffic was diverted off Broadway to Jefferson so that crews could shut off power to homes in the area.
Local American Red Cross volunteers John and Angele Judd were on the scene offering assistance to homeowners. They said only one man requested immediate assistance, but they said the provided information to other families in case they need help later on in the week.
The News-Sentinel will continue to update this story as more information becomes available.