Washington, September 24 (RHC)-- The U.S. Office of Personnel Management, OPM, says that hackers have actually gained access to 5.6 million fingerprint records rather than the one million originally reported by the federal agency.

The OPM made the announcement in a Wednesday statement that was "part of the government's ongoing work to notify individuals affected by the theft of background investigation records."

"Of the 21.5 million individuals whose Social Security Numbers and other sensitive information were impacted by the breach, the subset of individuals whose fingerprints have been stolen has increased from a total of approximately 1.1 million to approximately 5.6 million," it read.

The hack against federal employees, which took place in December 2014, is already the biggest one against the government in the US history. Those whose fingerprints have been hacked are particularly more vulnerable as there is no way to change them.

OPM, however, said "the ability to misuse fingerprint data is limited" yet warned that the "probability could change over time as technology evolves."