Police say a number of cash machines in Hull may have been targeted by criminals.
Officers were called on Monday following reports of tampering with machines in the Anlaby Road and Holderness Road areas.
Nobody is thought to have had any money stolen when using the cash machines, but damage had been caused to the front of the machines.
Police are now urging people to take extra care when using ATMs. Card skimming or card cloning devices are used by fraudsters to capture credit and debit card details from the public at cash points, ticket machines and retail outlets. The terms 'skimming' or 'cloning' are used to describe how a criminal copies a card's electronic data which is then used to recreate an exact copy of your card and gain access to your money. For information about what to look out for, visit www.crimestoppers-uk.org or call Action Fraud on 0300 123 2040.