Shoppers in Surrey have been warned to be on their guard for "Lebanese loops" being used by thieves to steal money from cash machines.
The loops are usually a strip of metal or plastic which retains a bank card when it is inserted into a machine.
Thefts have been reported in the borough of Woking, outside the Co-op stores in Horsell and St John's.
Police said money was fraudulently obtained after criminals had observed the victim entering their Pin number.
Officers have advised members of the public that if possible they should not leave the scene if their card is retained but call for help and inform their bank to prevent cash from being stolen.