Riots: Gloucester police attacked with rocks and bottles
Police officers came under attack from youths throwing rocks and bottles in Gloucester city centre on Tuesday.
Thirteen people including a girl, 16, were arrested following the disturbance which started at about 23:00 BST.
Assistant Chief Constable Ivor Twydell said: "Clearly the community is as appalled as we are about the behaviour of these mindless thugs."
Police have called for any visual evidence of the disturbances, such as photographs to be sent to the force.
He said: "Our officers are working through a large amount of intelligence and information from the community and as a result a number of arrests will happen throughout the day and coming days."
One shop was looted at about 02:30 BST on Wednesday. The newsagent on Tredworth Road had cigarettes and alcohol stolen and considerable damage was caused to it, police said.
A 26-year-old man from Gloucester was arrested on Wednesday afternoon on suspicion of burglary.
Fire crews were also involved in the incidents overnight and were called to tackle a blaze in Brunswick Road.
The fire was in a building previously used by Gloucestershire College of Art and Technology which has been empty since the college moved out in 2007.
A Gloucestershire Fire and Rescue Service spokesman said it had received a number of calls saying a fire had started at the back of the building, which was due to be demolished.
"The indications were that it was a significant fire so we initially sent three fire engines... when crews arrived they were confronted by a developing fire in the 50m by 25m building," he said.
"The second floor was well alight."
The spokesman said 40 firefighters had worked for two hours to bring the blaze under control.
More than 100 firefighters tackled various fires in the city centre, he said.
Police said they dealt with up to 60 people on the streets in the city centre - many with their faces covered.
Shop windows were attacked and bins set on fire in the Barton Street area.
One woman who lives above a Coral bookmakers and did not want to be named, described the moment about 30 people targeted the shop.
"I woke up with the room moving and that shows how hard they were kicking the glass," she said.
"I looked down and they looked up but I didn't want to grab my phone straight away because they might have attacked.
"They were only interested in smashing up the glass. I didn't see their faces because they were all wearing balaclavas or scarves over their faces.
"It's just unbelievable. It was like a war zone down here. It was just horrendous. I have never seen anything like it."
A police spokeswoman said support had been called upon from colleagues in the Avon and Somerset force.
Earlier in the day, 22 Gloucestershire Police officers were dispatched to London to help the Metropolitan Police deal with anticipated violence.
The force spokeswoman said contingency plans had been in place in the county so their absence did not have a significant impact.
On Wednesday morning, a county council spokesman said the clean-up operation was complete.
In a joint statement, Paul James, the leader of Gloucester City Council, and Mark Hawthorne, leader of Gloucestershire County Council, said: "Let's be clear - we will come down hard on these people."
Detectives are appealing for anyone with photographs or video of the disorder to contact them.