A US tourist was seen grabbing a teenage 'pickpocket' by the ponytail and vowing not to let her get away before police arrested the young thief in Italy.

Footage of the incident, which took place on Thursday in the Santa Maria del Giglio area of Venice, shows the furious American tourist gripping the 14-year-old's hair before leading her out of a crowd of onlookers.

Local reports said the unnamed holidaymaker had spotted the teen sneaking her purse, which contained her money and passport, into her bag before she instinctively grabbed her ponytail.

But as the young girl struggles and screams at the angry tourist, she holds on tight telling her: 'You stole my purse with my passport in it.

'You are not getting away. I'm not stopping kid. You are not getting away.'