Manhattan district attorney Alvin Bragg said in an email to staff on Saturday that his office will "not tolerate attempts to intimidate our office or threaten the rule of law in New York."
The email was sent after former President Donald Trump posted on social media that he expects to be arrested in connection with the ongoing investigation by New York prosecutors into a hush money scheme involving adult film actress Stormy Daniels and called on his supporters to protest any such move.
Bragg said his office is coordinating with the New York City Police Department and the court to "ensure that any specific or credible threats against the office will be fully investigated and that the proper safeguards are in place so all 1,600 of us have a secure work environment," according to the email, which was first obtained by Politico.
Manhattan district attorney spokesperson Danielle Filson confirmed the contents of the email to CNN but would not provide further comment.
The district attorney added that his office "will continue to apply the law evenly and fairly, and speak publicly only when appropriate," as he said they do with all investigations.
CNN's John Miller reported Friday that meetings have been going on taking place among city, state and federal law enforcement agencies in New York City about security preparations for a possible indictment of Trump.