CHICAGO (CBS) — Due to a spike in fraudulent filings, Illinois has delayed processing state income tax returns.

State revenue departments across the U.S. have reported a rise in filings using stolen personal information.

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TurboTax has temporarily stopped processing state income tax returns for the same reason.

In response to the increase in fraud, the Illinois Department of Revenue has been installing safeguards to prevent identity theft when tax returns are filed.

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“We continue to ask people just to be patient. We’re taking these extra measures to protect them, and to ensure that their tax return gets to them, and not to somebody else,” Illinois Department of Revenue spokesman Terry Horstman said.

Horstman would not say what kind of extra security is in place.

“We cannot discuss the security measures. Those are kept under wraps. It’s just so that we do not tip off any of those individuals that are trying to pass themselves off as somebody else,” Horstman said.

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The state of Illinois is accepting electronic tax returns, and will begin processing them next week.