The deceased were identified as Kolpona, 35, Jannat, 13 and Kauser, 8.
The details about the deceased could not be known immediately.
The fire broke out from a mosquito coil at a tin-shed house in Bauniabad area around 4:30am, said Rasel Shikder, duty officer of fire service control room.
On information, two firefighting units rushed to the spot and doused the fire around 6:30am.
Later, they recovered the charred bodies from the house.