U.S. President Donald Trump made a rare concession to critics on Wednesday when the White House rescinded an invitation to cartoonist Ben Garrison to attend Trump’s much-hyped social media gathering. The backlash followed Garrison’s invitation, which he posted to Twitter, after a cartoon that the Anti-Defamation League labeled “blatantly anti-Semitic” resurfaced.

Trump plans to meet with prominent conservative social media figures on Thursday at the White House forum where he is set to reiterate frustrations with big tech firms for allegedly suppressing conservative voices.

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Pro-Trump online personalities, many of whom are known conspiracy theorists, will get together to discuss what they say is censorship on social media platforms. Twitter, Facebook, Google and Reddit are not attending.

Trump lashed out in a Twitter post Thursday, just before the event, at various social media companies and traditional news firms, saying, "The Fake News is not as important, or as powerful, as Social Media" and criticizing what he said was unfairness by some firms.

"A big subject today at the White House Social Media Summit will be the tremendous dishonesty, bias, discrimination and suppression practiced by certain companies," Trump wrote. "We will not let them get away with it much longer."

Included on the White House guest list are controversial figures like conservative radio host Bill Mitchell, a right-wing meme maker who goes by the name Carpe Donktum and discredited “citizen journalist” James O’Keefe.

Bill Mitchell has been a central figure in boosting the QAnon conspiracy theory, using his radio show to promote believers of the theory that a so-called “deep state” is working to derail the Trump administration. Mitchell was also a key figure in promoting bogus sexual harassment allegations against Democratic presidential candidate Pete Buttigieg and October of 2018, and has suggested the U.S. government should put George “Soros in prison and seized his assets as an enemy of the United States.”

Carpe Donktum once won an Infowars “meme contest” and has been a repeated guest on Alex Jones' controversial conspiracy outlet. Media Matters notes that Donktum was also a regular contributor to Reddit subreddit “r/The_Donald,” which has been quarantined for calls to violence.

Media Matters for America's Alex Kaplan notes that O'Keefe once pled guilty to a misdemeanor for an incident in which he entered former Louisiana Senator Mary Landrieu's office under false pretenses. O'Keefe also once “detailed his plans to infiltrate and smear progressive organizations on the voicemail of Dana Geraghty, an employee of liberal philanthropist George Soros’ Open Society Foundations. “

Florida Congressman Matt Gaetz will also be in attendance. Gaetz is known for falsely suggesting Soros was funding a migrant caravan and inviting a far-right Holocaust denier to the State of the Union address.

Turning Point USA founder Charlie Kirk, right-wing YouTube channel Prager University and Human Events publisher Will Chamberlain will also be in attendance.

The White House has said Trump would deliver remarks at the event and that about 130 people would attend, without providing a guest list.

Trump made social media a key part of his 2016 presidential campaign but he and other Republicans have long claimed that online platforms employ tactics to silence their voices, allegations that major social media companies have denied.

Reuters contributed to this report