NEW YORK (AP) —TurboTax said Friday, it has temporarily stopped processing state tax returns due to an increase in fraudulent fillings.

Intuit Inc., the company behind popular tax preparation software TurboTax, said state agencies have reported a rise in fillings that are using stolen personal information.

The company is working with security company Palantir to investigate the problem. So far, Intuit says there was no security breach of its systems. Instead, it believes personal information was taken elsewhere and used to file returns on TurboTax.

Intuit said state tax returns already filed since Thursday will be transmitted as soon as possible. Users can still submit their federal income tax returns.

TurboTax processed 30 million tax returns last year.