(The Center Square) – The Internal Revenue Service is warning taxpayers of several tax scams.

The scams cover four transactions involving charitable remainder annuity trusts, Maltese individual retirement arrangements, foreign captive insurance, and monetized installment sales.

"The IRS views the four transactions listed here as potentially abusive, and they are very much on our enforcement radar screen," IRS Commissioner Chuck Rettig said.

Soon, the IRS will release the final eight potential tax scam threats to complete this year's "Dirty Dozen" list, an annually published list of scams the IRS sees as the most threatening to taxpayers.

They also warn taxpayers of online advertised schemes that could lead to potential unlawful action and anything that seems "too good to be true."

"Taxpayers can help stop these arrangements by relying on reputable tax professionals they know they can trust," Rettig said.

Many people also still have backlogged returns. According to the National Taxpayer Advocate, the IRS has 6 million unprocessed individual returns, 2.3 million unprocessed amended individual returns, and over 2 million unprocessed employer's quarterly tax returns.

The IRS advises taxpayers to look over their returns carefully before submitting them, as "Taxpayers are legally responsible for what's on their return," said Rettig.

"A key job of the IRS is to identify emerging threats to compliance and inform the public so taxpayers are not victimized, and tax practitioners can provide their clients the best advice possible," he added.