MILWAUKEE (CBS 58) -- Heavy smoke filled a home near North and Grant early Thursday, Feb. 19, as firefighters say they rushed inside to search for people reported trapped on the first and second floors.

The Milwaukee Department of Emergency Communications began getting calls about the fire around 2:29 a.m., according to the Milwaukee Fire Department. Callers told dispatchers several people were still inside, prompting officials to send extra paramedics before crews arrived.

Firefighters say they saw thick smoke pouring from the first floor, with people trying to get out through windows. Crews faced intense heat and near-zero visibility as they searched for the source of the fire and anyone still inside. Ladders went up to second-floor windows and a first-floor porch to help with rescues.

Four people were rescued. Paramedics took one person to the hospital with injuries believed to be non-life-threatening. Others were checked at the scene and declined further treatment.

Firefighters later found one person dead inside.

The fire is believed to have been contained to the first floor. Investigators are working to determine the cause.

The home is considered uninhabitable.