Anonymous officials make claims about alleged 'intelligence' that is said to show 'Iranian threats' against U.S. 'interests'. Iran, it is claimed, has this or that malign motive to do such. Routine military rotations to the Middle East are then declared to be 'in response' to the claimed 'threats'.
The media, either played like a fiddle by the administration or willing accomplices, repeat each and any such nugget thrown at them without any second thought. Anti-Iranian lobbyist are presented as 'experts' to reinforce the messaging.
Here are some examples of the above methods.
NBC News headlines:
Trump's top intelligence and military advisers held unusual meeting at CIA on Iran, officials say
Current and former officials said it is extremely rare for senior White House officials or Cabinet members to attend a meeting at CIA headquarters.