One of the US government's biggest contractors revealed Wednesday that its computer systems were hit by hackers, according to the Washington Post.
US Investigations Services, which performs government background checks, said the breach most likely involved the theft of personal information from US Department of Homeland Security employees.
"Experts who have reviewed the facts gathered to-date believe it has all the markings of a state-sponsored attack," the contractor said in a statement on its website. "We will support the authorities in the investigation and any prosecution of those determined to be responsible for this criminal attack."
The scope of the breach is unclear, but to be safe the DHS has suspended its work with the contractor.
"Our forensic analysis has concluded that some DHS personnel may have been affected, and DHS has notified its entire workforce" DHS spokesman Peter Boogaard told the Post. "We are committed to ensuring our employees' privacy and are taking steps to protect it."
This isn't the first time the US government has been the focus of what looks like a state-sponsored cyberattack. For years, the US has claimed hackers linked to the Chinese military have been snooping on government computers. However, the Chinese government has flatly denied it is involved in any cyber-espionage or hacking. Over the years, Iran and some Eastern European countries have also been blamed for carrying out cyberattacks.