Facebook has removed Trump campaign ads for using a symbol linked to Nazis.

The ads — which reportedly ran a day earlier, on June 17 — featured an inverted red triangle, according to Media Matters. That symbol was used in Nazi concentration camps to mark political prisoners, according to the United States Holocaust Memorial Museum.

Facebook, which has a general policy of allowing political advertising, told Digital Trends the Trump ads were “violating our policy against organized hate.”

“Our policy prohibits using a banned hate group’s symbol to identify political prisoners without the context that condemns or discusses the symbol,” a Facebook spokesperson said. Facebook did not answer questions from Digital Trends about why the ads had been allowed on its platform in the first place.

In a statement to Digital Trends, Trump campaign Director of Communications Tim Murtaugh claimed the inverted triangle was “used by Antifa, so it was included in an ad about Antifa.” Murtaugh also said Facebook had an emoji that looked similar to the symbol used in the ad.

“It is ironic that it took a Trump ad to force the media to implicitly concede that Antifa is a hate group,” he said.

There is no evidence the symbol is widely used by so-called Antifa groups, which operate largely independently of each other.

The incident is one of many controversies Facebook has faced over its political policies. The company has taken flak in the past for its role in the spread of misinformation.

Earlier this year, the company maintained its stance that it would not prevent political campaigns from lying in ads, but would instead provide tools to keep users informed. Facebook’s latest move has been to allow users to opt out of seeing political ads entirely.

Facebook CEO Mark Zuckerberg also was criticized by Facebook employees for his policy of allowing Trump comments to not be moderated.

In an op-ed for USA Today, Zuckerberg said the company was committed to free speech, saying: “We have rules against speech that will cause imminent physical harm or suppress voting, and no one is exempt from them. But accountability only works if we can see what those seeking our votes are saying, even if we viscerally dislike what they say.

“Ultimately, I believe the best way to hold politicians accountable is through voting, and I believe we should trust voters to make judgments for themselves.”

This is an emoji. 🔻

It's also a symbol widely used by Antifa. It was used in an ad about Antifa.

It is not in the ADL's Hate Symbols Database. pic.twitter.com/AY1YRxduf4

— Trump War Room (@TrumpWarRoom) June 18, 2020