Four 12-year-old boys were robbed by older boys in a Barton Seagrave park.
The incident took place at about 6.10pm on Saturday (March 4) in Grays Field Recreation Area.
The boys were approached by two teenagers, who police believe were aged 14 or 15.
They threatened the younger boys and made them hand over three mobile phones.
Police are investigating and are urging anyone with information to contact them.
Witnesses or anyone with information should contact police on 101 or Crimestoppers anonymously on 0800 555111.