A teenager brandished a knife after asking whether a 13-year-old boy in Ipswich had a phone or money.
The incident happened outside the Royal George pub in Colchester Road at around 12.45pm on Sunday, Suffolk police said.
A 13-year-boy was cycling towards Sidegate Lane when he was stopped by another youth, also on a bicycle, who asked if he had a phone or money.
When the victim refused, the suspect then produced a small knife.
The boy escaped unharmed and nothing was stolen.
The suspect is described as around 16 years of age, of small build and was wearing black clothing, a black face covering and white trainers, and was riding what was believed to be a red bicycle.
Anyone with information related to the incident is asked to contact Suffolk police, quoting reference 37/51889/20.
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