The video -- an edited version of the church massacre scene from the film "Kingsman: The Secret Service" -- was reportedly played at a pro-Trump conference by his supporters at his Trump National Doral Miami resort last week.

In the vid, the fake Trump begins a killing spree at the "Church of Fake News" of the major media outlets and news sites like Politico, NPR, Slate, The Hill, HuffPo and Vice News ... along with the activist movement Black Lives Matter.

He also assaults or murders critics like John McCain, Mitt Romney, Maxine Waters, Rosie O'Donnell, Bernie Sanders, Adam Schiff and Barack Obama ... before putting a stake in the head of a person with a CNN logo for a face.

The extremely graphic video is being blasted by the media and politicians, with CNN saying ... "Sadly, this is not the first time that supporters of the president have promoted violence against the media in a video they apparently find entertaining — but it is by far and away the worst."

It called for Trump and his entire administration to denounce it "in the strongest possible terms," adding ... "Anything less equates to a tacit endorsement of violence and should not be tolerated by anyone."