Even before a 20-year-old man took shots at former President Donald Trump in Pennsylvania, the U.S. Secret Service had reportedly already been on high alert about an assassination plot ... but coming from an entirely different place.

CNN reported today Iran had been planning some kind of attack against Trump ... and the intelligence about the Iranian plot was credible enough that officials in U.S. security agencies were taking it quite seriously.

KNX chief correspondent Charles Feldman talked with Evan Perez, he's CNN's senior justice correspondent and helped to break this story.

There is no known connection, at this point, between the Iranian assassination plot and the Pennsylvania man who actually tried to kill Donald Trump.