Unloading of cargo from the Bangladeshi vessel at the Al Hamriya port has been completed
Shahbagh Police Station OC Abul Hasan said an explosion of a transformer triggered the fire around 8:45pm on Wednesday.
Several units of firefighters brought the fire under control after more than an hour's efforts.
No casualties were reported, New Market Police Station OC Atiqur Rahman said.
Electricity supply to the neighbourhood was disrupted while police restricted traffic in the area to help the firefighters.