The public have been warned by police not to use Santander cash machines over fears several have been "compromised".
Forces in Lancashire and Cheshire said they have received reports of issues with some of the bank's ATMs.
The warning from Lancashire Police follows calls about suspicious devices on the bank's machines across the county last week.
Officers were concerned criminals targeted the machines in a bid to steal card details and cash, and urged those who have lost money to contact Santander.
But the bank said only five ATMs had been tampered with and these were shut down on police request. None of its customers had reported being defrauded, a spokeswoman said.
She added: "Santander was contacted this weekend by police who requested that five ATM machines in the North West and Lancashire area be shut down due to potential criminal activity and vandalism.
"The five ATMs in question were shut down immediately. The Santander ATM network remains fully operational and we are assisting the police with their enquiries in relation to the five ATMs in the Lancashire area.
"Customers are always advised to remain vigilant and if concerned about any other ATM machines, they should contact the police immediately and not use them."
Earlier, Lancashire Police tweeted: "Security at Santander ATMs in Lancs has been compromised. Advice is not to use them. If you have lost money please contact the bank and 101."
Cheshire Police also issued a warning to avoid Santander machines in Wilmslow, near Manchester.
The force tweeted: "Cheshire Police have received reports of issues with Santander ATM's in Wilmslow. Please do not use the machines and call your bank and 101."
A spokesman for the Lancashire force said it is feared the issue could be more widespread.
He said: "We are advising the public to be vigilant, in particular of Santander machines, but of any cash machines.
"Report anything suspicious, have a visual check of the cashpoint and if in doubt leave it and go somewhere else."
"It's spread across the whole of Lancashire so it's highly likely other forces may have had reports."
The force also issued advice to bank customers, including not to use a cash machine if it appears to have been tampered with and shielding the keypad when entering the PIN.