Personal information at least 25,000 government workers has been compromised in a data breach at US Investigations Services, a company that does background checks for the Department of Homeland Security, Reuters reported on Friday.

An unnamed agency official said that the impacted employees will be notified over the next few days.

Earlier this month, US Investigations Services disclosed the data breach but did not reveal its size. The company described the attack as having “all the markings” of a state-sponsored hacking, according to a release. The information gleaned could be used to intimidate workers to get ahold of sensitive government information, the Reuters report said.

“We are working closely with federal law enforcement authorities and have retained an independent computer forensics investigations firm to determine the precise nature and extent of any unlawful entry into our network,” the company said in a statement.

US Investigations Services employs over 5,700 workers and says it’s the largest provider of background investigations to the federal government.