The gas cylinder exploded while being refilled at a filling shop in the main Bela bazaar of Lasbela, the police said.
The flames engulfed other gas cylinders in the shop and spread to other shops, destroying at least four of them and around two dozen motorbikes parked in the vicinity, police added.
Lasbela deputy commissioner Murad Kasi said that twenty people received burn injuries, including the owner of the shop, in the cylinder explosion.
Police and Levies officials immediately rushed to the spot to shift them to hospital, local officials said. (ILKHA)