A teenager was punched to the head and knocked unconscious before he was then robbed of his mobile phone, cash and tobacco, police have said.
The attack and robbery happened on The Racecourse, at around 12.15pm on Friday, when a 17-year-old boy was walking towards Bailiff Street and was attacked.
When he regained consciousness he saw a group of seven boy running away.
One was described as white, aged 16 to 17, of large build with short dark hair. He was wearing black jeans and a black hooded top with a blue logo on the chest.
A second offender is described as a black boy, aged 17, of skinny build with short dark hair. He was wearing black jeans and a black hooded top.
The other five are described as young black men or teenagers.
Police say the victim received a head wound and required hospital treatment for his injuries.