Tactics employed by right-wing extremist groups are now being used by extremists on the left, report finds

Trailers on a construction site for a youth detention center burn after protesters targeted them during protests in Seattle on July 25. (Editor's note: Part of this photo has been blurred because of profanity.)

(CNN)Social media posts from far-left extremist groups conveying hateful, and at times violent, sentiments against police surged during the recent period of protests and civil unrest, according to a new report.

The findings were published Monday by the Network Contagion Research Institute (NCRI), a non-partisan organization that tracks hate and misinformation on social media.
The authors wrote that tactics employed by right-wing extremist groups, such as the use of memes and codewords to share ideas and organize offline activity, are also being used by extremist groups on the left.
White supremacist groups pose a much more significant threat in the US than far-left networks or other extremist groups, according to an analysis from the Center for Strategic and International Studies.
But there is now evidence to support that anarchist and socialist militant groups have also used internet platforms to plan and coordinate real-world attacks, the authors of the NCRI report write. Notably, researchers say leftist extremist networks organized and coordinated a campaign on July 25 in cities including Seattle and Portland, where riots and property damage were later reported.
Though the report's findings are preliminary, the researchers warn that the proliferation of extremist rhetoric on the left is also something that policymakers and authorities need to pay attention to.
"This is a structure that has been operating in plain sight," Joel Finkelstein, director of NCRI and the report's corresponding author, told CNN. "We don't know how big it is yet. We don't know how interconnected it is. What we've learned from our research is that it exists."

Groups used memes and codewords, report says

The authors, who have previously researched threats against law enforcement from the Boogaloo movement, analyzed more than 10 million social media posts on platforms including Twitter and Reddit.
They found that incendiary terms and slogans were being used in memes and as codewords during the social justice protests and unrest across the nation.