Extremists are conning elderly citizens in the United Kingdom out of their life savings to fund the Islamic State (ISIS, ISIL), reports the Daily Mail.

According to the International Business Times (IBT), British authorities have arrested two men accused of funding ISIS “via a phone scam that targets elderly people in Britain.”

The Daily Mail reports that a third man was arrested on suspicion of fraud and money laundering.

“Masquerading as policemen, the extremists cold-call their targets and claim their bank details have been compromised,” explains the Daily Mail.

“The frightened and unsuspecting victims are told to switch all their cash to another account to keep it safe,” it adds. “But the account belongs to the fraudsters and the money vanishes. It will be used to buy weapons, ammunition and combat gear for Islamic State militants.”

U.K. police have warned the public about the scam, which reportedly mirrors swindles used by domestic fraudsters.

“Members of the public are strongly advised, if you receive a call like this from someone claiming to be a police officer, hang up the phone, wait at least five minutes to make sure the phone line has cleared, or use another phone line, before ringing the phone number on your bank card,” said a Scotland Yard police spokesman.

“The arrests form part of an ongoing fraud investigation, whereby unsuspecting vulnerable and elderly victims are cold-called on their home phone by a suspect impersonating a police officer, informing them their bank account has been compromised and deceiving victims into transferring money to an account under the control of the suspect,” added the spokesman.

One of the victims was fleeced out of £150,000 ($225,555). Meanwhile, two other pensioners in their 80s lost £130,000 ($195,481) between them.

“Officers are investigating a large-scale fraud linked to UK extremists traveling to Syria,” said the Scotland Yard spokesman.

ISIS is considered one of the wealthiest terrorist groups in history.

The jihadist group may have access to more than $1.5 billion in cash, notes the Daily Mail, adding, “Its funds come from the revenue of captured oil fields, business extortion and hostage ransoms.”

“We are seeing diverse fraud including substantial fraud online, abuse of the benefits system, abuse of student loans, in order to fund terrorism,” reportedly said Terri Nicholson of the Metropolitan Police Service’s counterterrorism command in November.

“We have had a number of cases in recent times where student loans have been abused to fund both crime and terrorism,” added Nicholson. “We have seen some cases where virtual currency is being considered and used by both criminals and terrorists. And so we are increasing our understanding of the abuse of those methods.”

The U.K. Charity Commission is investigating 86 aid organizations it believes could be at risk of diverting funds to terrorists, reports the Daily Mail.

“High street banks are closing or freezing accounts held by UK charities working in conflict zones…Salaries paid to the bank accounts of aid workers who live outside the U.K. have also been delayed or blocked,” it adds.

London authorities have seized more than $2 million in donations destined for criminal and terrorist groups in the past two years.