Thames Valley Police is appealing for witnesses after three boys were robbed and assaulted in Oxley Park on Friday.
At around 8.30pm three boys aged 13 and 14 were sitting in the underpass below the H6 near Stanwyck Lane when they were approached by three youths.
One of the offenders asked the time and demanded that the victim gave him his phone, he then punched the victim in the face.
A second victim was also threatened and punched while the third victim was pushed to the ground and kicked repeatedly.
The offenders then made off with one of the victims mobile phones, a Blackberry Curve.
All three offenders were white, one was 5ft 10ins aged around 16-17 years-old, medium build, and was wearing a black hoody and light tracksuit bottoms.
The second offender was 5ft 8ins, aged 16-17 years-old, medium build and was wearing black tracksuit bottoms.
The third offender was 5ft 8ins, aged around 15-years-old, medium build, and was wearing a black hoody, a black cap with white writing on the front and black tracksuit bottoms.
The victims suffered bruising but did not need treatment in hospital for their injuries.
Anyone with information that could help police with their enquiries should contact Det Con Wendy Cissell at Milton Keynes police station via the new 24-hour non-emergency single number 101. If you do not want to speak to the police, call the Crimestoppers charity anonymously on 0800 555 111.