Arrests in Stoke after Port Vale and Wolves football match
Police were pelted with missiles and made 23 arrests after a disturbance broke out following a football match.
Staffordshire Police said a "minority of fans" confronted each other after a League One fixture between Port Vale and Wolverhampton Wanderers.
The force said officers were "confronted by a significant group" of "violent" Port Vale fans.
Trouble spilled over into Burslem town centre in Stoke-on-Trent after the final whistle.
Port Vale lost the game 3-1 to visiting local rivals Wolves.
Staffordshire Police said it was now looking at CCTV footage from the day's fixture, in a bid to trace everybody who had a hand in causing trouble.
Port Vale said it would fully support any police action against any of its fans involved.
Extra policing had been brought in for the game.
Missiles and bottles were thrown at officers and a marked police car was vandalised.
Two adults suffered dog bites from police dog units and were treated by paramedics, according to the force.
Those arrested included nine people detained before kick-off. Another four were arrested during the match for offences including going on to the pitch and setting off flares.
Police said they were "disappointed" a "significant number" of fans had decided to cause trouble at the fixture, despite significant preparations between club officials and officers that were aimed at preventing trouble.
Staffordshire Police said fans from both sides had been involved but praised a group of Wolves fans who "co-operated with police by waiting in the away coach park while police worked to clear the area".
"We are disappointed by the actions of this significant number of so-called fans who attended today's fixture intent on becoming involved in disorder," said Ch Insp Dave Bird, of Staffordshire Police.
He added: "All those arrested will be questioned about their actions and CCTV evidence from today will be examined by officers.
"The behaviour of this significant minority doesn't represent the club or our city."
Meanwhile, Bill Lodey - Port Vale club secretary, said: "The club are bitterly disappointed regarding the violence that has been reported in Burslem town centre.
"We will fully support any actions taken by the police in apprehending those responsible and they can expect severe penalties."