CCTV images have been released of two men after a serious assault on the day of the Old Firm derby.

A 27-year-old man was left with a serious head injury after two men targeted the victim and his friend in the Glasgow city centre just hours after the 1-1 draw between Celtic and Rangers at Celtic Park on March 12.

The four men got involved in an altercation outside the premises of William Hill bookmakers on Sauchiehall Street before the victim was then attacked inside the shop by two men at around 3.50pm.

The 27-year-old was taken to Glasgow Royal Infirmary after the assault while his friend, aged 26, was punched in the face but declined medical attention.

Police investigating the assault are now keen to trace the two men seen in the images.

The first man they wish to speak to is believed to be in his mid-40s and is described as bald with a heavy build.

At the time of incident he was wearing a blue polo shirt.

The second man is slim, with short dark hair and was wearing a blue shirt on the day of the assault.

Anyone who recognises these men or has information about the incident is asked to contact Greater Glasgow CID via 101. Information can also be given anonymously to Crimestoppers on 0800 555 111.

The Scottish Premiership clash ended in a 1-1 draw after a late Rangers equaliser.

Police made a total of 11 arrests in or around Celtic Park on the day of the game.