Elon Musk’s aides at the cost-cutting “Department of Government Efficiency” have gained access to the sensitive personal data of millions of federal employees. According to reports by Reuters and Musk Watch,

Three U.S. government employee unions filed a lawsuit Monday against the Treasury, alleging that its sharing of confidential information with the Elon Musk-run Department of Government Efficiency violated the law.

Musk’s team at the Department of Government Efficiency was given access to the Treasury Department’s payment system over the weekend.

Elon Musk is threatening to fire federal employees who leak information as he and President Donald Trump unleash unprecedented chaos on the government. On Sunday, a user posted an anonymous “operational security reminder” on Reddit’s FBI forum with advice for sharing information so it can’t be traced back to the source.

A federal prosecutor appointed by President Donald Trump said on Monday the FBI was investigating the “targeting” of staff involved in Elon Musk‘s effort to slash the size of the US government. Career government officials have reportedly sought to counter efforts by Musk aides working with his Department of Government Efficiency to gain access to troves of classified information without proper authorization.