An "aggressive" phone scammer claiming to be a police officer threatened to arrest people who wouldn’t give him their personal details.
Residents in the Crickhowell area have reported receiving the calls and Dyfed-Powys Police has confirmed it is a scam.
The force reminding people not to give their personal details over the phone or email and to contact Action Fraud if they suspect someone has attempted a scam.
Police said: "The caller is very aggressive on the phone, pretending to be a member of the police.
"The caller states that you have ’committed some kind of fraudulent offence and if you do not provide your personnel details you will be arrested.
"This is a scam designed to obtain personnel details for criminal activities. Do not give anyone your personnel details over the phone or via email. If you suspect a scam has been carried out please contact Action Fraud and report online at www.actionfraud.police.uk/ or ring 0300 123 2040."