The fire was noticed around 7 p.m. at the warehouse in the old city's main market, Sadar Bazar, a senior fire official said.
Despite efforts by the fire fighters to douse the flames, the warehouse -- housed in a three-storeyed building in the congested market -- was gutted.
Fire fighters initially found it difficult to reach the spot since the approach to the market has been constricted due to encroachments by traders.
A senior official said an inquiry will be held to ascertain how a fire crackers warehouse was set up in a highly congested market.
The cause of the fire or the financial loss incurred could not be known immediately.
