Far-right groups celebrated on social media Tuesday night after President Trump responded to a debate question about white supremacists by saying that the extremist Proud Boys, a male-only group known for its penchant for street violence, should “stand back and stand by.”

The comments almost instantly got enshrined in memes, including one depicting Trump in one of the Proud Boys’ signature polo shirts. Another meme showed Trump’s quote alongside an image of bearded men carrying American flags and appearing to prepare for a fight.

These and other laudatory images spread with particular speed on the conservative social media site Parler and also channels on the encrypted chat app Telegram, according to researchers. One prominent Proud Boys supporter on Parler said Trump appeared to give permission for attacks on protesters, adding that “this makes me so happy.”

On the fringe social media site 4chan, an anonymous supporter wrote, “STAND BACK AND STAND BY … SOMEONE HAS TO STOP THESE FAR LEFT RIOTERS,” according to SITE Intelligence Group, which tracks far-right groups.

It also found that Telegram channels devoted to neo-Nazis and white supremacists portrayed Trump’s comments as signals of support for them. The Proud Boys dispute characterizations of them as white supremacists, but their actions often are touted by white supremacists and others on far-right political fringes.

“He legitimized them in a way that nobody in the community expected. It’s unbelievable. The celebration is incredible,” said Rita Katz, executive director of SITE. “In my 20 years of tracking terrorism and extremism, I never thought I’d see anything like this from a U.S. president.”….