Gavin Newsom, California's Democratic governor who is widely expected to run for president in 2028, has accused President Donald Trump of ordering a criminal investigation into him and his wife.
Mr Newsom said federal agents had in recent days been knocking on the door of members of his family, friends and former employees, demanding records and digging through years-old documents.
The governor has emerged as an early frontrunner to become the Democrats' presidential nominee. He has won praise from many in his party for his willingness to attack Mr Trump in his own combative style, calling the President "unhinged" and mocking him on social media.
"Donald Trump isn’t just coming after me because of my mean tweets," Mr Newsom said in a video statement posted on X.
"He’s coming after me because I am considering running for president."
The Justice Department and the White House did not immediately comment.
Mr Newsom said investigators have not found a crime but were "simply trying to find one".
Speaking directly to Mr Trump in the video, Mr Newsom said: "You can subpoena my records. You can investigate me. You can harass me. Put my name on every and any enemies list you have, but leave my wife and family out of your personal vendetta."
The two men have clashed publicly over many issues, including climate change and Mr Trump's deployment of National Guard troops to California last year.
Mr Trump has previously said he would support Mr Newsom being arrested over the governor's alleged obstruction of immigration enforcement in the Golden State.
Since Mr Trump returned to office for a second term, his Justice Department has targeted several of the President's perceived political enemies with criminal prosecutions, pursuing charges against former FBI director James Comey, New York state Attorney General Letitia James and former national security adviser John Bolton.
"They are doing to me - and my wife - what they did to Jerome Powell, James Comey, Tish James, Adam Schiff, the six members of Congress who made a video he didn't like, and a woman a jury found Donald Trump had sexually abused," Mr Newsom said. "Now it's my turn."
