Preet Bharara, former U.S. Attorney for the Southern District of New York, addressed the situation surrounding reporting that said special counsel Robert Mueller has impaneled grand jury.

On Twitter, Bharara asked why people were "hyperventilating" over the convened grand jury.

Noting Mueller has hired 16 prosecutors, Bharara said this was standard procedure for a case of this nature. He added "this will take time."

Bharara was fired as a U.S. attorney in March by Trump, along with 46 other U.S. attorneys. He has been critical of the president ever since.

Reports emerged on Thursday that Mueller impaneled a grand jury in Washington, D.C., regarding the ongoing Russia probe into President Trump's 2016 campaign.

Reuters reported that subpoenas have already been issued related to Donald Trump Jr.'s meeting with a Kremlin-linked lawyer in June 2016.