Police have released images of 19 people they want to speak to about a large-scale disturbance before the Scottish League Cup final in Glasgow.
Violence and disorder broke out in the city centre ahead of the match between Celtic and Rangers at Hampden Park on Saturday 15 December.
Footage on social media showed large groups of fans, some wearing Santa hats and face coverings, charging down Argyle Street and setting off flares ahead of kick-off.
The force has urged anyone who recognises those pictured to contact them.
People who witnessed the disorder in the city centre are also asked to get in touch.
Video taken on the day showed large groups of fans walking through the city centre from about 13:00, escorted by police.
However, violence soon erupted, with one group charging down Argyle Street towards the Trongate.
Shoppers could be seen screaming and running back indoors to avoid the rush.
Online footage showed one football fan fall to the ground while others ran around him. A short time later a flare was set off near a shop doorway.
An officer was then seen using his baton on a number of fans passing by.
A shopper told BBC News they were forced to take refuge in a nearby shop “for their own safety”.
CCTV footage from Gallagher’s Bar on Howard Street showed a masked man being punched in the face as he tried to enter the pub of Celtic supporters.
Moments later a flare was thrown through the doorway while fans charged along the street outside.
During the disorder, a Police Scotland officer was injured after missiles were thrown and a 26-year-old man was also taken to hospital after being seriously assaulted.
Officers were authorised to use stop and search powers, including removing items being used to conceal identity.
Action Images/ReutersFlares were later set off during the match itself.
Celtic took home the cup after winning 5-4 on penalties in a 3-3 draw against Rangers.
First Minister John Swinney condemned the behaviour of a “minority of fans” as “completely unacceptable”.
He added: “It caused fear and distress and alarm to people who were enjoying Christmas shopping in advance of the football game.
“The clubs have got a responsibility to make sure that their fans behave properly.”
