U.S. Marshals have warned federal judges of unusually high threat levels as tech billionaire Elon Musk and other Trump administration allies ramp up efforts to discredit judges who stand in the way of White House efforts to slash federal jobs and programs, said several judges with knowledge of the warnings.

In recent weeks, Musk, congressional Republicans and other top allies of U.S. President Donald Trump have called for the impeachment of some federal judges or attacked their integrity in response to court rulings that have slowed the Trump administration’s moves to dismantle entire government agencies and fire tens of thousands of workers.

Musk, the world’s richest person, has lambasted judges in more than 30 posts since the end of January on his social media site X, calling them “corrupt,” “radical,” “evil” and deriding the “TYRANNY of the JUDICIARY” after judges blocked parts of the federal downsizing that he’s led. The Tesla CEO has also reposted nearly two dozen tweets by others attacking judges.

Reuters interviews with 11 federal judges in multiple districts revealed mounting alarm over their physical security and, in some cases, a rise in violent threats in recent weeks. Most spoke on condition of anonymity and said they did not want to further inflame the situation or make comments that could be interpreted as conflicting with their duties of impartiality. The Marshals Service declined to comment on security matters.