NEW YORK (Reuters) - U.S. Republican presidential nominee Donald Trump paced, frowned and physically loomed at times over Democratic rival Hillary Clinton during Sunday night’s town-hall debate, prompting bewilderment and mockery from some on social media.

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The online reaction underscored the contentious tone of the encounter in St. Louis in which Trump and Clinton hurled insults at each other less than a month before the Nov. 8 U.S. presidential election.

Twitter users seized on Trump’s body language, with some remarking that he appeared to have “stalked” Clinton around the stage. The criticism came as the Republican faces a political storm after being caught on a leaked 2005 videotape making lewd and demeaning remarks about women.

“#Trump’s body language [was] bizarre,” wrote Twitter user Sheena (@texdakota). “Pacing, insulting, standing right behind her.”

“Trump’s body language freaked me out,” wrote Charlotte (@charlotteirene8). “I get very uncomfortable when men stand behind me, especially like that.”

A spokeswoman for Trump did not immediately respond to a request for comment.

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Clinton’s performance inspired online criticism as well. “Clinton could have done better,” tweeted ryank (@ryantkelly). “Didn’t seem as hungry, as able to get under his skin tonight.”

Sentiment on Trump’s performance was 66.9 percent negative, according to an analysis by social intelligence firm Brandwatch of Twitter posts during the debate, while Clinton’s was 57.8 percent negative.

The debate, which featured questions from audience members, was the most tweeted-about debate ever, with more than 17 million tweets, said Twitter spokesman Nick Pacilio.

Trump’s statement that he and running mate Mike Pence differed on their approach to military intervention in Syria was the most-talked-about moment of the night on the microblogging site.