Three private cars were burnt as the gas cylinder of a car exploded at Mohakhali in the city on Friday evening.
The incident happened in front of the Expanded Programme on Immunisation (EPI) building behind Mohakhali kitchen market.
However, no causalities were reported.
Firefighters extinguished the blaze after half an hour of efforts.
Deputy Assistant Director of Fire Service and Civil Defence Masudur Rahman Akand said they primarily suspected that the fire originated from the explosion of the gas cylinder of an old car parked in front of the EPI building.
He told reporters at the spot that the southern portion of the EPI building had been damaged in the fire.
The eyewitnesses said people of the surrounding areas were panicked at the terrible sound of the explosion.
Fire Service control room official Mohammad Ali said 10 blaze-fighting units rushed to the spot on information.
But three firefighting units from Tejgaon zone had already doused the blaze.