Two teenagers were attacked as they enjoyed the sunshine over the bank holiday weekend.
The two boys aged 15 and 16 were walking through Shelf Hall Parkat 4.30pm on Saturdaywhen they were approached by two men.
One of them punched the 16-year-old several times in the face, leaving him with a bloody nose.
They then told the teens to empty their pockets and stole a mobile phone, an Ipod, earphones and cash.
Police are appealing for any witnesses who saw the attack or the two men drinking in the park before the incident.
The first attacker is described as a white male, six feet tall, of a slim build with short black hair.
He was gaunt looking with stubble and was wearing a dark green t-shirt with a large logo and blue denim jeans.
The second suspect was a white male, six feet tall, of a fat build and wearing a grey t-shirt.
Anyone with information should call police on 0845 6060606.