Denzel Washington was fired up, going full "Training Day" as he let loose on a group of paparazzi ... and possibly some autograph seekers ... who clearly pushed the wrong buttons.
Check out the video ... the actor was all smiles, posing for pics outside NYC's Museum of Modern Art on Wednesday -- but it seems at least one person in the overzealous crowd crossed a line ... and Denzel didn't hold back checking that person ... in what appeared to be a heated exchange.
You can't catch most of the convo, but you can hear Denzel pretty much warning them to chill out and wait patiently and respectfully ... saying they'd get a chance to see him on the flip side -- or maybe not, depending on their behavior.
It's not super clear what exactly set Denzel off -- he's usually cool, calm and collected IRL --but the whole exchange felt like a throwback to his iconic "King Kong" scene from the 2001 classic, "Training Day."
Either way, you definitely don't want to be known as the bonehead who ticked off Denzel ... right before he was set to honor his buddy Samuel L. Jackson!