FBI warns iPhone and Android users to hang up the call if you hear this

There's a new, nasty scam on the scene that the FBI warns poses a real threat to most people with a smartphone.

Federal agents are raising the alarm over a new scam that involves a particular phone call and some smart tech trickery.

Scam calls aren't exactly new, but this is particularly foul, as the FBI says many iPhone and Android users could struggle to spot the fraudster creeping up on them.

The scam can be quite convincing (Getty Images)

That's because the scam pretends it's a technical support line, a bank, the US Customs and Border Protection (CBP) or even your local police force, and can be quite convincing as the scammers have been able to 'spoof' the caller ID number.

What happens next is that victims are tricked into moving money from their account or installing dangerous software on their device.

As is typical of such attacks, the con artist will make you think the matter is urgent, to give you less time to think.

And malware can be an absolute nightmare to get rid of - if you even know it's there.

Take, for instance, this cop's stark warning about QR codes. Just one simple scan of a seemingly innocuous code and a stranger has complete access to your phone. That's your credit card info, online banking details, pictures, phone numbers - the lot.

The scammers can be convincing (Getty Images)

Anyway, the FBI's advice to protect yourself and your device from a costly mistake is incredibly simple.

If you receive an unsolicited call where you haven't called them first, hang up the phone, even if it sounds or seems to be a trustworthy source.

The FBI says the chance of such a call being legitimate is so small that it's not worth taking the risk.

The scammers might contact you to say that your bank account is under attack or that you need to transfer funds to avoid being arrested by police.

Police departments from Virginia to New York have had such situations on their hands as officers received reports from victims that fraudsters have been posing as local law enforcement on the phone and coercing victims into sending money.

According to Forbes, the new scamming campaign has been going on for several weeks now with police warning that 'this type of scam has occurred throughout the region, including Alexandria, and across the country.'

The force continues: "Scams have variations but generally the caller will identify themself as a law enforcement officer and tell the victim, falsely, that a warrant has been issued because they missed a court date, did not show up for jury duty, have an overdue fine or something similar, and they will be arrested unless they pay right away.”

Officers say this situation doesn't happen but scammers have been known to 'use the name of actual deputies or police officers' and have been able to disguise their phone number 'to make it look like they are calling from a local enforcement agency.'

Likewise, if you receive a call from a police officer demanding money or some other bizarre request, the FBI says to hang up the phone and call your local law enforcement yourself to explain what has happened.

The CBP has issued a similar warning about a 'spike in phone calls' from concerned people who had calls from scammers posing as CBP employees 'seeking information about suspected illegal activity'.

CBP said it 'will not call a suspect or a victim requesting money or social security numbers' nor make calls 'threatening citizens that law enforcement is on the way or promising money for information'.