With a small yet telling gesture, U.S. President Donald Trump generated international rebuke and scorn on Thursday after video surfaced of him rudely pushing a fellow head of state out of the way during a photo opportunity at the NATO summit in Brussels.

The clip shows Trump stepping in front of Montenegro Prime Minister Dusko Markovic while pushing him aside with one hand. Trump then plants his feet and straightens his jacket without regard for Markovic. Montenegro is the newest member of the alliance.

Watch:

During his visit to NATO headquarters, Trump moves in front of Montenegro Prime Minister Dusko Markovic to be in front of the group pic.twitter.com/kYDfshnVrp — POLITICO (@politico) May 25, 2017

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And in slow motion:

Slow motion Trump at NATO physically moves aside Montenegro PM Dusko Markovic to get in front! pic.twitter.com/1FQsoDJR2i Aggression intended. — R Beaupre (@benaxor) May 25, 2017

Trump was already receiving low marks and a cold reception for his remarks at the summit, but the lack of etiquette opened a fresh round of criticism for the president on his first trip representing the U.S. abroad.

Social media users quickly condemned and ridiculed Trump's behavior:

Tweets about Trump Montenegro