Facebook on Thursday said it removed ads attacking antifa and “far-left groups” run by President Donald Trump’s reelection campaign for violating its rules against “against organized hate.” The ads featured an inverted red triangle, a symbol used by Nazis to identify political prisoners in concentration camps.

“We removed these posts and ads for violating our policy against organized hate,” said a Facebook spokesperson on Thursday. “Our policy prohibits using a banned hate group’s symbol to identify political prisoners without the context that condemns or discusses the symbol.”

The ads, which were spotted earlier by Media Matters and The Washington Post, started running on Wednesday and showed up on Facebook pages for Trump, Vice President Mike Pence, Team Trump and other pages. Before they were removed on Thursday, the ads had racked up more than 800,000 impressions on the president’s Facebook page alone, according to data in Facebook’s Ad Library. 

In total, the Trump campaign ran eighty-eight ads featuring the inverted red triangle on Facebook, according to the Post. The ads used the symbol alongside text warning that “dangerous MOBS of far-left groups are running through our streets and causing absolute mayhem,” and asking people to “stand with your President and his decision to declare ANTIFA a Terrorist Organization.” 

Antifa, short for anti-fascists, is an overarching description of far-left militant groups that confront white supremacists and neo-Nazis at rallies and other events. Trump in May tweeted that the US would designate antifa a terrorist organization. 

The Trump campaign defended its ads on Thursday, saying the inverted red triangle is a symbol commonly used by antifa. 

“The inverted red triangle is a symbol used by Antifa, so it was included in an ad about Antifa,” said Tim Murtaugh, director of communications for the Trump campaign, in an emailed statement. “We would note that Facebook still has an inverted red triangle emoji in use, which looks exactly the same, so it’s curious that they would target only this ad.” He added that the inverted red triangle isn’t included in the Anti-Defamation League’s database of symbols of hate.

Facebook has previously pulled ads run by the Trump’s reelection campaign related to the 2020 US census and immigration.