Iran has threatened to attack American interests world wide if the US strikes at Iran's nuclear weapons programme.
Three questions spring to mind.
Number one: How will they do this? They do not have the military capability to attack US interests other than through terrorism - which is, of course, illegal under "international law".
Secondly: What do they mean by US interests? In the event of war between the US and Iran, both sides are obliged to avoid civilian casualties.
Finally: What's new?