Skimming devices which enable thieves to steal money from bank cards have been found on two cash machines in Lochaber.
Police are warning local people and visitors to the area to be vigilant after the discovery at Mallaig.
And anyone who used the affected ATMs after 8am on Friday is being warned to check their bank account and to report any unauthorised activity.
A police spokesman said: “During Saturday morning, a member of the public discovered a skimming device on an ATM at Royal Bank of Scotland.
“Inquiries also discovered that an ATM at Bank of Scotland had been tampered with.
“We are asking members of the public to pay close attention to see if there is anything unusual or suspicious about cash machines.”
The police spokesman urged people to be vigilant, by checking cash machines for anything “out of the ordinary” before inserting their card and shielding their pin with their free hand.
Anyone who finds any suspicious device or has any information about these incidents should call 101.