Minnesota officials said late Thursday it would immediately stop accepting tax returns filed through TurboTax, a popular tax preparation software, due to possible fraudulent activity.

Revenue Commissioner Cynthia Bauerly said the state would continue accepting tax returns from other software brands and through traditional filing methods.

Nonetheless, the sudden halt to TurboTax-filed returns is expected to cause many to change how they file 2014 income tax returns. With nearly 30 million customers nationwide, TurboTax accounts for between 60 to 65 percent of the market. Bauerly said TurboTax accounts for a large number of returns filed in Minnesota, which has about 2.7 million filers annually.

State officials had limited information on the scope of fraudulent activity but said some Minnesota taxpayers reported attempting to use TurboTax to file their taxes only to find a return had already been filed. The agency said its computer systems were not breached.

Assistant Revenue Commissioner Terri Steenblock said they discovered problems with some returns Wednesday night and by Thursday they began blocking returns submitted through TurboTax, which is owned by Intuit Inc.

Steenblock said they are working with Intuit to address the problems and learn more about the issue. "The most important thing is making sure we protect taxpayers," Steenblock. 

Officials said that taxpayers affected may call Intuit at a dedicated phone number, 800-944-8596, beginning Friday morning for more information.