Illinois residents are being warned about a phone scam in which con artists pose as IRS officials demanding unpaid taxes.

Attorney General Lisa Madigan's office issued a warning Wednesday.

She's seen an increase in the number of complaints to her office in recent weeks from Illinoisans who have been contacted by scammers pretending to be government officials. The scammers make bogus claims that the residents are under investigation or that they owe money to the Internal Revenue Service.

The scammers can trick phone caller ID devices and cause them to display what appears to be legitimate call from the IRS, with identifiers such "IRS" or the (202) area code for Washington.

Madigan is urging Illinois residents to report scam calls to her Consumer Fraud Bureau.

Joshua Lott, Getty Images