Although no direct or public threat has been made by Iran to attack the US homeland - and there is a current ceasefire in effect in the conflict between Iran and Israel - the country has a long history of sponsoring violent attacks in the US, says Dr Lorenzo Vidino from the George Washington University Program on Extremism.

The FBI has ramped up its efforts to monitor potential threats to the U.S. from Iran following President Donald Trump’s decision to attack the country’s nuclear facilities, two people briefed on the matter told Reuters on Tuesday.

The FBI is returning national security agents who were ordered to focus on immigration cases back to their old jobs due to concern about potential threats from Iran