Police have issued a warning to users of automatic cash machines in Sussex after five skimming devices were found.
The devices were spotted on machines in North End, Queen's Road and West Street, Brighton by an off-duty Kent police officer.
Evidence was found that they been fitted and removed from several others.
Sussex Police said the devices, which were difficult to spot, had readers to record cash card details and cameras to film users' PIN numbers.
A police spokeswoman said it was difficult to know how long the devices, at Lloyds, HSBC and Tesco branches, had been in place or how many users were affected.
Pc Philip Dodd said the devices were fixed with a distinctive black mastic adhesive.
"When looking at other ATMs in the city, we have discovered the residue of this adhesive on a number of them," he said.
"It is reasonable to assume that these machines have been targeted in the past, but we are unable to establish when."
He warned users in Sussex to look at cash machines closely and report any suspicions to their banks or the police.
"If you have any doubts, don't use them or make sure that you cover your keying hand with your other hand when you put in your PIN."
He appealed to anyone with information about the devices to come forward.