CONMEN posing as energy company workers are trying to trick residents into handing over their bank details.
The scammers have called up scores of people across Glasgow pretending to be ScottishPower employees.
One said he was working for the energy supplier and that he could help customers lower their bills.
One resident said: "I had a call asking me about my account and telling me about how I could clear my debt.
"The man seemed very plausible, but then he asked me to give my bank details over the phone.
"I knew that was nonsense because legitimate companies never ask for that kind of information over the phone.
"But not everyone knows that and it is easy to see how some people – particularly the elderly – could be taken in by it."
ScottishPower urged customers to report anything suspicious to police.
A spokesman said: "If you receive a call from someone stating they are from ScottishPower and you have doubts then do not disclose any details.
"Ask for the caller's name and department and call us immediately using the number on your bill or our website.
"We will be able to confirm if the caller is genuine.
"ScottishPower will not ask you to reveal your bank account number or any other banking details to verify your identity."
Police also warned people never to give bank details over the phone.
Anyone with information is asked to call police on 0141 532 2000