More than 40 firefighters were called to tackle a fire in Lewes High Street which broke out in the roof space between a shop and a restaurant.
Fireworks stored in the building caused loud explosions
Fireworks stored in the building caused loud explosions at the height of the blaze but no injuries were reported.
Emergency teams said there were 10 appliances in the road, which had to be closed, causing major traffic delays.
Crews expected to be at the scene into the night, a spokeswoman for East Sussex Fire and Rescue Service said.
The fire broke out at about 1500 BST, above a clothing store, she added.