Police in Manchester have released CCTV images showing up to 200 football fans chasing officers and attacking one of them after the Uefa Cup final.
The footage also shows Glasgow Rangers fans tripping up a Greater Manchester police officer and jumping on him after the match with Zenit St Petersburg.
Assistant Chief Constable Justine Curran described the fans as being "like a pack of baying wolves".
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The Scottish Conservatives said using riot police was an "overreaction".
They have demanded an inquiry into the policing operation.
Uefa has praised the police and city council for their handling of the occasion.
Police made 42 arrests and ambulance crews dealt with 52 cases of assault after the match, in which Glasgow Rangers were beaten 2-0 by Zenit St Petersburg.
Assistant Chief Constable Curran said violent clashes were sparked when police officers came under a "severe level of attack".
Riot police were deployed after a city centre big screen failed and several arrests were made, including six men who were held after a Russian fan was stabbed inside the City of Manchester stadium.
The police officer whose attack was captured on CCTV video suffered bad bruising to his arms and body and hurt his elbow.
Greater Manchester Police said a total of 15 officers suffered minor injuries and a police dog cut its paw after treading on broken glass.
Screen inquiry
Despite the scenes, council leader Sir Richard Leese said the city would not be put off hosting future international sporting events.
Sir Richard said it was one of the biggest movements of people ever seen for such an event, and paid tribute to the authorities for the handling of the crowds.
He also said there would be an inquiry into the failure of the screen in Piccadilly Gardens.
The company behind the five screens erected in the city centre, Lightmedia Display, said the failure was due to a technical signalling problem.
The city council said next week's Champions League Final between Manchester United and Chelsea, in Moscow, would not now be shown on big screens in Manchester.