Before rioters stormed the US Capitol, Trump supporters called for violence online

(CNN Business) While many Americans were stunned as they watched rioters descend on the Capitol and clash with police, there has been chatter for days on various social media platforms about the prospect of Wednesday's protests turning violent.

Ahead of protests organized to contest the formal counting of electoral votes in Washington DC, calls for violence could be found in discussions on Twitter, TikTok, right-wing platform Parler and an online forum formed last year in support of Donald Trump, according to research from nonpartisan nonprofit Advance Democracy.

On Wednesday afternoon, a pro-Trump mob stormed the Capitol, pushing through barriers set up around the building and tussling with officers in full riot gear. One woman was shot. Windows were broken. At least one Trump supporter was pictured standing at the Senate dais, while another breached House Speaker Nancy Pelosi's office. A Capitol police officer in the House chamber told lawmakers that they may need to duck under their chairs.

Before the protest, several TikTok videos promoting violence racked up thousands of views, with one user advocating for protestors to take their "mother-[expletive] guns" to DC, according to Advance Democracy. One TikTok video containing violent rhetoric had nearly 280,000 views.

TikTok removed two of the offending videos after they were flagged by CNN Business.

"Hateful behavior and violence have no place on TikTok. Content or accounts that seek to incite, glorify, or promote violence violate our Community Guidelines and will be removed," a TikTok spokesperson said.

On Twitter, there were more than 1,250 posts from accounts related to the QAnon conspiracy theory about Wednesday's protests containing terms of violence since January 1. The most basic QAnon belief casts President Trump as the hero in a fight against the "deep state" and a sinister cabal of Democratic politicians and celebrities who abuse children.

One post from a QAnon-related account retweeted a post with a baseless conspiracy theory that Democrats, Black Lives Matter activists, and Antifa protestors were planning to kill Trump supporters and advocated for whoever noticed these individuals to get "rid of them."

"Over the last few days we've seen unprecedented calls for violence online among Trump's most ardent supporters," said Daniel J. Jones, president of Advance Democracy.

He said this has been fueled by President Trump and his election lawyers who have been making "nonstop false claims" about the presidential election being "rigged," as well as by 13 Republican senators objecting to the Electoral College results. "[This] has served to legitimize Trump's position and the conspiracy theorists," Jones said. "The unprecedented violence we're seeing today is a direct result of the president's rhetoric."

The riots highlight the dangerous consequences of online misinformation spilling over into the real world.

"First there was volatile rhetoric online, then explicit calls to violence and now people are acting on those calls in the nation's capital and flagrantly breaking the law," the Anti-Defamation League said in a statement. "More than anything, what is happening right now at the Capitol is a direct result of the fear and disinformation that has been spewed consistently from the Oval Office."

The ADL also said President Trump has promoted sedition and incited violence and called on social media companies to suspend the president's accounts immediately, "as they would do for anyone else advocating disinformation and promoting violence. It's time."

Facebook condemned the violent riots at the US Capitol on Wednesday, but stopped short of saying Trump would be blocked from the social media platform.

"The violent protests in the Capitol today are a disgrace," said Facebook spokesman Andy Stone in a statement. "We prohibit incitement and calls for violence on our platform. We are actively reviewing and removing any content that breaks these rules."

Facebook also removed President Trump's video from Wednesday afternoon addressing his supporters, according to Stone. In the video, Trump urged Capitol rioters to "go home" but struck a sympathetic tone and reiterated his debunked claims of election fraud. Meanwhile, Twitter moved to restrict engagement with tweets by President Donald Trump and others that have been labeled "due to a risk of violence."

When asked for comment, Twitter pointed CNN Business to its official Twitter account, which posted a statement saying: "In regard to the ongoing situation in Washington, D.C., we are working proactively to protect the health of the public conversation occurring on the service and will take action on any content that violates the Twitter Rules."

Parler did not immediately respond to a request for comment.