Facebook said Thursday it has removed ads run by President Donald Trump's re-election campaign that featured a symbol that violated its policy against organized hate.

The ads attacked the far-left group Antifa, calling them "Dangerous MOBS" that were rioting around the country, CNN Business reported. The ads called on supporters to sign a petition in favor of Trump's call to make Antifa a terrorist organization. At issue, was a red, upside-down triangle featured in these ads, which the Anti-Defamation League said Thursday was similar to one used by Nazis for political prisoners.

The triangle used "is practically identical to that used by the Nazi regime to classify political prisoners in concentration camps," the Anti-Defamation League said Thursday.

ADL CEO Jonathan Greenblatt further blasted the advertisements in a tweet.

"The Nazis used red triangles to identify their political victims in concentration camps," Greenblatt tweeted. "Using it to attack political opponents is highly offensive. @POTUS' campaign needs to learn its history, as ignorance is no excuse for using Nazi-related symbols."

According to Facebook, the ads violated the company's 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," Andy Stone, a Facebook spokesperson, told CNN.

Historical records show that a red triangle was laid over a yellow triangle to classify political prisoners in Nazi camps.

"Jewish prisoners were identified by a yellow star,'" Montreal Holocaust Museum website states. "If they were imprisoned for another reason, a triangle of the appropriate color was added to their badge. Therefore, if a Jewish prisoner was also considered a political opponent, a red triangle was sewn over the yellow triangle."

In response to criticism, Tim Murtagh, a spokesman for the Trump campaign, said "the red triangle is an Antifa symbol."

However, a common image of the Antifa logo shows two flags surrounded by a circle, which dates back to opponents of the Nazis in 1930s Germany, Axios reported.

The progressive advocacy group, Bend the Arc: Jewish Action, also condemned the symbol's use.

"The president of the United States is campaigning for reelection using a Nazi concentration camp symbol," the group tweeted. "Nazis used the red triangle to mark political prisoners and people who rescued Jews. Trump and the RNC are using it to smear millions of protesters. Their masks are off."

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