Worcestershire police are warning the public to be vigilant when withdrawing cash after card cloning equipment was discovered.
The warning comes after a cloning device was found on a Nationwide machine in High Street, Evesham, on Good Friday.
Further equipment was discovered in Worcester earlier this month and there have been further incidents of card cloning or "skimming", in the Midlands this year.
The fraudster makes a copy of the card, the PIN and further information to use at any cash machine.
A South Worcestershire Police spokesman said: " Common methods are a minicamera to read PIN numbers and a device retaining the card for the criminal to use later.
"If anyone thinks they've discovered a device call the police and we will deal with it." The Midlands is a hotspot for card crime, according to Apacs, the electronic payments industry association.
Card fraud cost the region £21.5 million in 2004 and machine fraud increased 81 per cent last year in the UK to £74.6 million. Police hope the new Chip and Pin system will reduce card fraud.
Steve Cowdry, of Nationwide, said: "Be on your guard. Also take care to shield your PIN when using your card in shops."