A man suffered a serious head injury in an attack at a bookmakers hours after the Old Firm derby.

The 27-year-old and his friend were targeted by two men in Glasgow city centre on Sunday afternoon.

Police confirmed one line of enquiry in their investigation was whether or not the attack was linked to the SPFL match between Celtic and Rangers earlier that day.

The group became involved in an "altercation" outside the premises on Sauchiehall Street.

The victim was then attacked inside the shop by the two men at around 3.50pm.

Officers said 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.

One attacker is described as being of heavy build and around 35 to 45. He was wearing a blue T-shirt and jeans. The other attacker was in his mid-40s and was wearing a blue T-shirt.

Police made a total of 11 arrests at or around Celtic Park after the 12pm kick-off, which finished 1-1.

Anyone with information is asked to contact the police on 101.