Facebook has removed a campaign advert by Donald Trump and Mike Pence that featured a symbol once used by Nazis.
The upside-down red triangle was used by Nazis to designate political prisoners, communists, and others in concentration camps.
The $17,000 (£13,670) ad campaign had launched on Wednesday.
Facebook said it had removed the ads on Thursday because they violated “our policy against organised hate”.
Nathaniel Gleicher, the company’s head of security policy, told a hearing of the house intelligence committee that Facebook does not permit the use of symbols of hateful ideology “unless they’re put up with context or condemnation”.
“In a situation where we don’t see either of those, we don’t allow it on the platform and we remove it. That’s what we saw in this case with this ad, and anywhere that that symbol is used, we would take the same action,” he added.
But Trump communications director Tim Murtaugh claimed the symbol was used by Antifa so had been included in an ad about the anti-fascist group, which Trump has blamed for violence during recent Black Lives Matter protests.
Mark Bray, a Rutgers University historian, told the Associated Press that the symbol is no longer widely used by anti-fascist groups in Europe or US Antifa groups.
Mr Murtaugh also said the symbol was not in the Anti-Defamation League’s database of hate symbols but the league responded to this by saying the database only includes symbols that are still in use.
ADL chief executive officer Jonathan Greenblatt said: “Whether aware of the history or meaning, for the Trump campaign to use a symbol – one which is practically identical to that used by the Nazi regime to classify political prisoners in concentration camps – to attack his opponents is offensive and deeply troubling.”
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The Facebook move comes after the social networking website’s chief executive Mark Zuckerberg was criticised for not taking action against earlier Trump posts described as spreading misinformation and encouraging violence against protesters.
Late on Thursday, Mr Trump posted two videos on Twitter, one of which was labelled by the social networking website as “manipulated media”.
The video, titled Terrified Todler (sic) Runs From Racist Baby had been created to make it look as if it was from CNN but Twitter’s labelling made clear that the post breached its synthetic and manipulated media policy.
The policy says a user “may not deceptively promote synthetic or manipulated media that are likely to cause harm”.
It comes amid growing concern that players in the US or from outside could be spreading misinformation to influence the November presidential election.
Also speaking at the house intelligence committee hearing was Twitter’s public policy strategy and development director Nick Pickles, who said that the threat had not diminished – it had simply evolved.
Commenting on China’s likening of police brutality in the US to the criticism it faced for its treatment of protesters in Hon Kong, Mr Pickles said: “That shift from platform manipulation to overt state assets is something that we’ve observed.”