(CNN) – If you get a call from someone claiming to be with the IRS, be suspicious.
Federal authorities are spreading the word about what they're calling the largest nationwide phone scam ever.
Officials say more than $1 million has been stolen from thousands of unsuspecting people.
The calls involve an IRS impostor who will tell you that you owe taxes that must be paid with a prepaid debit care or wire transfer.
Authorities say the scammers threaten arrest, deportation or loss of a business or driver's license for those who don't pay up.
According to the U.S. Inspector General, real IRS officials typically reach out by mail first, rather than by phone, and don't demand immediate payment by debit card, credit card or wire transfer.
The IRS asks anyone who has received one of the phony calls to report it.
The say they've gotten more than $20,000 reports of scam calls.