A total of 13 people have been arrested in connection with alleged public order offences prior to the kick-off of a Scottish Premier League match, according to police.
Police in Glasgow were called to the Chrystal Bell pub on the Gallowgate in the city at 1pm where a large number of people were gathering.
Officers believed they were going to carry out an illegal street procession to Celtic Park where Celtic were due to play Aberdeen at 3pm.
They were told by police that they could walk towards the football ground on the pavements but not on the roads. Police said this message was ignored and the group became aggressive.
A spokesman for Strathclyde Police said: "The crowd, many of whom were wearing similar hooded tops and scarves to hide their identities, appeared to be attempting to stage an illegal street procession and officers were deployed to prevent this.