Violence and disorder have broken out in Glasgow city center ahead of the Scottish League Cup final between Celtic and Rangers at Hampden Park.
Images on social media show large groups of fans charging down Argyle Street before kick-off, setting off flares near fearful shoppers.
Police officers can be seen using batons against the running fans, some of whom were wearing Santa hats and covering their faces.
The force said missiles had been launched and windows had been broken. He said officers had been authorized to use stop and search powers, including removing items used to conceal identity.
The powers will remain in place until 9pm in areas including the city center and parts of the south side, the far east and in South Lanarkshire.
Many trains had been canceled before the 15:30 start with ScotRail warns of driver shortage.
From 1:00 p.m. large groups of fans could be seen walking through the city center, escorted by the police.
However, violence soon broke out and a group attacked down Argyle Street towards Trongate. Shoppers can be seen trying to leave screaming and running inside to avoid the rush.
A football fan falls on the group while others run around him shortly before a flare is lit near the door of a store.
One shopper told BBC News he was forced to take shelter in a nearby store “for his own safety.”
An officer can then be seen using his baton against several passing fans.
Police Scotland said officers had been authorized to use stop and search powers under section 60 of the Criminal Justice and Public Order Act 1994.
This allows officers to stop people when appropriate and necessary, whether in vehicles or on foot.
Ch Supt Steve Dolan said: “Officers have had to act quickly and firmly to ensure public safety and reduce disorder.
“The use of weapons or violence will not be tolerated and officers will take action where necessary to ensure safety.
“It affects other members of the public and the vast majority of football fans who want to enjoy the cup final safely. “Officers will remain in the city while our operation continues and anyone with any concerns can approach them.”