Trump made the statement in a post on his Truth Social platform, saying he received the letter Sunday night. Such a letter can precede an indictment; Trump got one ahead of being charged last month in a separate investigation into his handling of classified documents.
A spokesman for special counsel Jack Smith, whose office is leading the investigation, did not immediately return an email seeking comment.
Prosecutors have cast a broad net in their investigation into attempts by Trump and his allies to block the transfer of power to President Biden.
Trump, who is currently the dominant early front-runner for the Republican nomination, is scheduled to travel to Iowa on Tuesday, where he is taping a town hall with Fox News host Sean Hannity.
Prosecutors in Georgia are conducting a separate investigation into efforts by Trump to reverse his election loss in that state, with the top prosecutor in Fulton County signaling that she expects to announce charging decisions soon.
In his post, Trump wrote that “they have now effectively indicted me three times … with a probably fourth coming from Atlanta” and added in capital letters: “This witch hunt is all about election interference and a complete and total (political) weaponization of law enforcement!”
Trump was indicted last month on 37 felony counts accusing him of illegally retaining hundreds of classified documents at his Florida estate, Mar-a-Lago. He has pleaded not guilty. A pretrial conference in that case was set for Tuesday in Fort Pierce, Fla.