A 16-year-old boy was repeatedly punched in the head after being asked for cigarettes in Aylesbury’s Vale Park.
The victim was with two friends when they were approached by three boys, who asked for cigarettes.
When he said he did not have any, the victim was grabbed by one of the boys.
The victim pushed him away, but he then attacked the boy before walking off in the direction of the Vale Retail Park shops.
The victim suffered bruising to his forehead but did not need hospital treatment.
The incident happened near the semi-circular covered seat at about 5.30pm on Sunday.
The suspect is Asian, aged 16 to 17, about 5ft 6ins or 5ft 7ins and of large build.
He was wearing a light blue hooded sweatshirt with white stripes on the arms, a brown T-shirt, and a black tracksuit.
He may have spoken with a slight Irish accent.
Anyone with information should contact PC Ian Glover by calling 101.
Alternatively you can call Crimestoppers anonymously on 0800 555 111.