FBI opens investigation into data breach at IRS

The FBI has opened an investigation into the recent data breach at the Internal Revenue Service, CNBC has learned Thursday.

RELATED: IRS says thieves stole tax info from 100,000

The FBI said that people contacted by the IRS should take the necessary steps to monitor and safeguard their online presence and information. Any suspicious activity should reported to the FBI at www.ic3.gov.

The investigation by the FBI indicates the breach was far more serious than previously thought.

This is a breaking news story. Please check back for updates.

This story originally appeared on CNBC.com