Man Moons Anti-ICE Protesters From Hotel Window, on Video

Anti-ICE protesters in Minnesota became unwilling astronomers Monday night ... taking in the full moon when a man dropped his pants and slapped his butt cheeks up against a hotel window.

The impromptu peep show took place at the SpringHill Suites by Marriott in Maple Grove, Minnesota, where demonstrators -- who believed outgoing United States Border Patrol Commander-at-Large Gregory Bovino and other federal agents were inside -- protested from the curb outside.

Their message wasn't well-received by one guy in the hotel standing near a window with a group of his pals ... who decided to lodge a counter-protest of his own -- by mooning the crowd.

His friends seemed to want no part in the action, taking off down the hallway when this dude's butt hit the window ... but the man doesn't care -- giving the protesters a show before flipping off the assembled crowd.

We reached out to the Department of Homeland Security ... and they could neither confirm nor deny whether federal agents were staying at the hotel. The protest outside the hotel was eventually broken up by law enforcement, who claimed the demonstration reached a point that was "no longer considered peaceful."

Demonstrations escalated in the Minneapolis area this weekend after Alex Pretti -- a 37-year-old United States citizen -- was shot to death in the street by DHS agents ... with video of the incident sparking outrage around the country ... this on top of ongoing protest in the streets following Renee Good's shooting death at the hands of ICE training agent Jonathan Ross, and other heavy-handed immigration-enforcement actions.