More likely, the story is designed to make the public believe that US propaganda is actually aimed at the "foreign adversary" rather than at the US population. The emotionally appealing bit is the idea that even if the story is fake, Iran is now thinking it is dealing with an adversary that has and is using tech that is right out of science fiction.

In reality, it's all aimed at us, the people. All of the "tough talk", the comments that appear intended for dissident groups within Iran, etc., is all meant to mislead the people (us) who can stop the war so we don't do so.

By Veritasium, for anyone else wondering whether to click

We know it's simple to detect someone's heartbeat from just colour changes of ones skin in a regular video taken with a phone camera. Wouldn't this be trivial with military level IR tech? Sounds way more likely than some amazing new top secret technology that is somehow filtering out every other magnetic field and can detect a heartbeat through mountains.

Back many years ago I worked on a research project which used UWB radar to detect breathing through walls / rubble / etc. But the distance was in the range of 1-10 meters. The application was to use such sensors for finding survivors after earthquakes etc.

If they can detect the faint signal of a heartbeat from so far away, why not instead deliberately transmit a weak, wider-bandwidth pseudorandom magnetic signal? Such a signal would be even harder to detect than a heartbeat without prior knowledge, yet easier to identify and track using a matched filter.

I think the link must be https://www.youtube.com/watch?v=SVTPv4sI_Jc