Police were bombarded by fireworks and missiles as they investigated a Bonfire Night incident in Cheltenham.
Firefighters were called to extinguish the bonfire
Officers were called to the Hesters Way estate after reports that fireworks were being thrown at cars on Princess Elizabeth Way.
Fireworks, stones and other objects were lobbed at them when they arrived and two patrol cars were damaged.
Five people are being questioned, say police. Around 30 people are estimated to have been involved.
They were called out by residents of New Zealand House who were concerned about a huge unlit bonfire which had been built behind the flats.
The bonfire was lit while officers were investigating a shed containing suspected stolen fireworks near the scene.
Fire crews were called to extinguish the bonfire after concerns for the safety of residents.