PHOENIX ' With the 2017 tax season underway, the IRS reminds seniors to remain alert to aggressive and threatening phone calls by criminals impersonating IRS agents. The callers claim to be IRS employees, but are not.

These con artists can sound convincing when they call. They use fake names and bogus IRS identification badge numbers. They may know a lot about their targets, and they usually alter the caller ID to make it look like the IRS is calling.

The victims are told they owe money to the IRS and must pay it promptly through a preloaded debit card or wire transfer. If the victim refuses to cooperate, they are often threatened with arrest. In many cases, the caller becomes hostile and insulting. Alternately, victims may be told they have a refund due to try to trick them into sharing private information. If the phone isn't answered, the phone scammers often leave an "urgent" callback request.

"The IRS warns seniors about these aggressive phone calls that can be frightening and intimidating. The IRS doesn't do business like that," said IRS Commissioner John Koskinen. "We urge seniors to safeguard their personal information at all times. Don't let the convincing tone of these scam calls lead you to provide personal or credit card information, potentially losing hundreds or thousands of dollars. Just hang up and avoid becoming a victim to these criminalsGÇÄ."

In recent years, thousands of people have lost millions of dollars and their personal information to tax scams and fake IRS communication.

Later this spring, the only outside agencies authorized to contact taxpayers about their unpaid tax accounts will be one of the four authorized under the new private debt collection program. Even then, any affected taxpayer will be notified first by the IRS, not the private collection agency (PCA).

The private debt collection program, authorized under a federal law enacted by Congress in 2015, enables designated contractors to collect tax payments on the government's behalf. The program begins later this spring. The IRS will give taxpayers and their representative written notice when their account is being transferred to a private collection agency. The collection agency will then send a second, separate letter to the taxpayer and their representative confirming this transfer. Information contained in these letters will help taxpayers identify the tax amount owed and help ensure that future collection agency calls are legitimate.

The IRS reminds seniors this tax season that they can easily identify when a supposed IRS caller is a fake. Here are four things the scammers often do but the IRS and its authorized PCAs will not do. Any one of these things is a telltale sign of a scam.

The IRS and its authorized private collection agencies will never:

• Call to demand immediate payment using a specific payment method such as a prepaid debit card, gift card or wire transfer. The IRS does not use these methods for tax payments. Generally, the IRS will first mail a bill to any taxpayer who owes taxes. All tax payments should only be made payable to the U.S. Treasury and checks should never be made payable to third parties.
• Threaten to immediately bring in local police or other law-enforcement groups to have the taxpayer arrested for not paying.
• Demand that taxes be paid without giving the taxpayer the opportunity to question or appeal the amount owed.
• Ask for credit or debit card numbers over the phone.

If you don't owe taxes, or have no reason to think that you do:

• Do not give out any information. Hang up immediately.
• Contact the Treasury Inspector General for Tax Administration to report the call. Use their "IRS Impersonation Scam Reporting" web page. You can also call 800-366-4484.
• Report it to the Federal Trade Commission. Use the "FTC Complaint Assistant" on FTC.gov. Please add "IRS Telephone Scam" in the notes.

If you know you owe, or think you may owe tax:

• Call the IRS at 800-829-1040. IRS workers can help you.

Remember, too, the IRS does not use email, text messages or social media to discuss personal tax issues involving bills or refunds. The IRS will continue to keep taxpayers informed about scams and provide tips to protect them. The IRS encourages taxpayers to visit IRS.gov for information including the "Tax Scams and Consumer Alerts" page.

Additional information about tax scams is available on IRS social media sites, including YouTube Tax Scams.