A 13-year-old boy suffered facial injuries after he was punched by two hooded robbers who stole his wallet in Banbury.
The victim and a 12-year-old boy were robbed in the Hillview recreation ground on Thursday at about 8.45pm.
One robber is described as white, aged between 16 and 18, wearing a dark hooded top and dark trousers. The other is mixed race, wearing a dark hooded top.
Pc Bryn Smith, of Banbury police, urged anyone with information to call 101 and said: “This offence is cowardly and completely unprovoked.”