President Donald Trump has taken an intense personal interest in ending the war between Ukraine and Russia, recently suggesting that “nothing” will happen until he has an official meeting with Russian President Vladimir Putin.

Anthony Guglielmi, chief of communications for the U.S. Secret Service said in a statement to ABC News that the agency "vigorously investigates anything that can be taken as a potential threat against our protectees" and is aware of the post made by Comey.

The Kremlin said on Friday that a meeting between Russian President Vladimir Putin and U.S. President Donald Trump was essential to make progress on Ukraine and other issues, but needed preparation and had to yield results when it happened.